Background: Branched-chain amino acid (BCAA) is involved in glucose and lipid metabolism and energy homeostasis, but whether its effects on maternal metabolism and offspring growth during lactation depend on dietary protein level remains unclear. Methods: C57BL/6J lactating dams were randomized after delivery to a normal-protein control group (CN, 20% protein), low-protein group (LP, 10% protein), CN + BCAA group (CNB), or LP + BCAA group (LPB) (n = 11/group). Maternal body composition, glucose and lipid metabolism, hepatic energy status, oxidative stress indices, and pup litter weight gain were assessed. Results: The LP diet reduced maternal body weight, pup litter weight gain, and glucose responses during the intraperitoneal pyruvate tolerance test (IPPTT), and increased hepatic lipid deposition and oxidative stress. BCAA supplementation increased pup litter weight gain under normal-protein conditions, but decreased maternal food intake and offspring growth under low-protein conditions. Metabolically, BCAA supplementation reduced the homeostasis model assessment of insulin resistance (HOMA-IR) and hepatic PEPCK1 activity under normal-protein conditions, while partially restoring IPPTT glucose responses and increasing hepatic PEPCK1 activity under low-protein conditions. In addition, BCAA supplementation reduced hepatic lipid deposition and ATP content at both protein levels. Notably, under low-protein conditions, BCAA supplementation increased serum β-hydroxybutyrate (β-HB), while alleviating hepatic oxidative stress. Conclusions: BCAA supplementation exerted opposite effects on offspring growth during lactation under different maternal dietary protein levels. These effects may be related to differential changes in maternal glucose and lipid metabolism and hepatic energy status, suggesting that BCAA supplementation during lactation should be evaluated according to maternal dietary protein level.

Background: Dietary metabolizable energy (ME) and crude protein (CP) levels are important for lactation performance and metabolic responses in dairy ruminants. This study aimed to evaluate the effects of dietary ME and CP levels on lactation performance and postprandial metabolic responses in lactating dairy goats. Methods: Goats were randomly assigned to a 4 × 4 two-factor Latin square experiment consisting of four 14 d periods. The dietary treatments were high energy, high protein (HEHCP); high energy, low protein (HELCP); low energy, high protein (LEHCP); and low energy, low protein (LELCP). Serial postprandial arterial blood samples were collected at 17 daytime time points to characterize temporal changes in plasma amino acids, biochemical parameters and hormones. Results: Increasing CP supply elevated milk yield (+6%) and lactose yield (+5%) but decreased milk fat yield (−8%; p ≤ 0.04). Increasing ME supply tended to enhance milk yield and milk fat yield and increased milk lactose content only under the high CP condition (ME × CP interaction: p = 0.04), suggesting that the response to ME supply depended partly on dietary CP level. High CP increased plasma branched chain amino acid concentrations, whereas high ME reduced Leu and Val under the high CP condition. Most plasma amino acids exhibited marked postprandial dynamics, decreasing initially and then stabilizing, with CP × time interactions observed for Leu, Met, and Phe (p ≤ 0.05). High ME decreased plasma AST activity and tended to reduce urea N concentration and also reduced ALT activity and increased glucose concentration under the high CP diet. Following morning feeding, plasma urea N showed a progressive postprandial decline (p = 0.02), with glucagon decreasing and both prolactin and growth hormone increasing, despite no dietary effects on mean plasma hormone concentrations. Conclusions: Overall, dietary ME and CP levels affected lactation performance and selected plasma metabolic indicators in lactating dairy goats. Coordinated energy and protein supply should be considered when formulating diets for lactating dairy goats. Serial postprandial sampling further revealed temporal changes in plasma metabolites and hormones, providing useful information for refining precision nutrition strategies during lactation.

The mammary gland undergoes continuous growth, differentiation, and cyclical remodeling throughout the whole life, with morphogenesis from the embryonic stage to adulthood being crucial and highly sensitive to nutritional supply. While moderate nutritional restriction in early life and subsequent restore can promote the tissues development such as muscle, its effects on the mammary remain largely unexplored and appear to depend critically on the development stage. Thus, the effects of moderated nutritional restriction in early life including embryonic (ER), suckling (SR), or pubertal (PR) periods on mammary development and subsequent lactation performance in mice were investigated in the present study. In this study, we imposed nutritional restriction on mice during either a single period or two periods. Mammary gland and serum samples were collected at maturity (56 d) and on lactation day 15 for hormonal, histological, and transcriptomic analyses. Our results demonstrate that ER enhances mammary development and adult lactation capacity by boosting proliferative activity and increasing the mammary stem cell content. In contrast, postnatal nutritional restrictions (SR and PR) disrupt normal gland morphogenesis by attenuating hormonal signaling responses and reducing stromal tissue remodeling. Notably, the adverse effects of SR on mammary morphology are reversible upon nutritional repletion, with no subsequent impact on milk production, whereas PR leads to a significant impairment in adult lactation. These findings reveal distinct regulatory mechanisms of nutritional intervention at various development stages and provide a foundational basis for optimizing lactational outcomes through targeted nutritional strategies.

Few studies have examined the effects of puerarin (PE) on ruminant parameters and methane production. Therefore, we determined the degradation of PE in the rumen and evaluated the effect of PE on in vitro fermentation, methanogenesis, and microbial community structure. A completely randomized design was used for the in vitro fermentation, and 4 gradient dosages of PE (0 mg/kg, 50 mg/kg, 100 mg/kg, and 150 mg/kg of DM) were applied in this trial. The in vitro fermentation was carried out in three runs at 6 h and 48 h, with four replicates per treatment per time point. Each run included 40 samples: eight treatments × four replicates and eight blank samples. Based on the fermentation results, both the PE treatments and the control group (CON) at 48 h were chosen for further analysis to explore the effects of PE on the bacterial community structure. Meanwhile, we determined the degradation rate and degradation products of PE in vitro ruminal fluid using high-performance liquid chromatography (HPLC). In this trial, PE may be isomerized into daidzin by rumen microorganisms; the in vitro degradation results of PE indicated that 70% of PE was degraded within 6 h, with the degradation rate reaching nearly 85% by 12 h. The concentrations of NH3-N and microbial crude protein (MCP) significantly increased linearly with the PE doses at 6 h (p = 0.01). The concentrations of MCP (p = 0.02) and propionate (p = 0.04) demonstrated a linear increase with increasing PE doses at 48 h. In contrast to microbial protein (MCP) and propionate, the acetate-to-propionate ratio decreased linearly with increasing PE doses at 48 h (p = 0.05). Additionally, the addition of PE linearly decreased methane production at 48 h (p = 0.01). Meanwhile, the relative abundances of g_UBA1217 (p = 0.03), g_UBA2810 (p = 0.04), and g_Succiniclasticum (p = 0.03) were significantly lower compared with the CON group. The results showed that PE can be degraded by rumen microflora. Furthermore, it can improve rumen fermentation parameters, increase the amount of protein synthesized by rumen microorganisms, and reduce methane production and the acetate-to-propionate ratio. PE could potentially be an effective strategy for methane mitigation; however, further research is needed to assess its in vivo effects in dairy cows over a longer period.

Tannins have been extensively studied to decrease nitrogen excretion, however, the effects of tannins on animal production were inconsistent. The objective was to evaluate the effects of a mixture of quebracho-chestnut tannin extract (QCTE) supplementation on the production performance, nutrient digestibility, rumen fermentation patterns, and N partitioning in dairy cows. Sixty multiparous Holstein cows (mean ± standard deviation; average 717 ± 51kg of body weight, 2.5 ± 0.2 of parity, 47 ± 1.9kg/d of milk production, 78 ± 3.2 d of days in milk were randomly divided into four groups. Cows in different groups were provided QCTE at doses of 0, 10, 20, and 30g/d per cow for 56 d. Although QCTE supplementation did not affect dry matter intake (DMI) and total-tract apparent digestibility of nutrients, milk yield and milk protein yield increased linearly (P = 0.01), and a trend for a linear (P = 0.07) increase in milk/DMI were observed with increasing QCTE supplementation. Increasing QCTE supplementation decreased the milk urea-N concentration and somatic cell count linearly (P < 0.05), tended to linearly (P < 0.1) decrease the concentration of blood urea-N and ruminal ammonia nitrogen, linearly (P < 0.05) increased levels of total antioxidant capacity and superoxide dismutase, and the molar proportions of ruminal propionate. Additionally, total N excretion was not affected by QCTE treatments, but QCTE supplementation linearly (P = 0.04) increased N utilization efficiency and tended to linearly (P = 0.1) decrease urea-N excretion in the urine. In conclusion, feeding QCTE at a dose of 30g/d per head to cows in early lactation could increase antioxidant enzyme activities, improve production performance, and decrease environmentally labile urinary N excretion under the conditions of the study.

Adequate energy supply is a crucial factor for maintaining the production performance in early lactating cows. Adding fatty acids to diets can improve energy supply, while the effect could be related to the chain length and degree of saturation of fatty acids. This study was conducted to evaluate the effect of different ratios of palmitic acid (C16:0) to oleic acid (cis-9 C18:1) on the production performance, nutrient digestibility, blood metabolites and milk fatty acids profile in early lactating dairy cows. Seventy-two multiparous Holstein cows (63.5 ± 2.61 d in milk) blocked by parity (2.39 ± 0.20), body weight (668.3 ± 20.1 kg), body condition score (3.29 ± 0.06), and milk yield (47.9 ± 1.63 kg) were used in a completely randomized design. Cows were divided into 3 groups with 24 cows in every group. Cows in 3 treatments were provided iso-energy and iso-nitrogen diets, whereas the C16:0 to cis-9 C18:1 ratio was different: (1) 90.9% C16:0 + 9.1% cis-9 C18:1 (90.9:9.1); (2) 79.5% C16:0 + 20.5% cis-9 C18:1 (79.5:20.5); (3) 72.7% C16:0 + 27.3% cis-9 C18:1 (72.7:27.3). Fatty acids were added at 1.3% in dry matter basis. Although the dry matter intake fat-corrected milk yield and energy-corrected milk yield were not affected, the milk yield, milk protein yield and feed efficiency increased linearly with the increasing of cis-9 C18:1 ratio. The milk protein percentage and milk fat yield did not differ among treatments, whereas the milk fat percentage tended to decrease linearly with the increasing of cis-9 C18:1 ratio. The lactose yield increased linearly and lactose percentage tended to increase linearly with increasing cis-9 C18:1 ratio, whereas the percentage of milk total solids and somatic cell count decreased linearly. Though the changes of body condition score were not affected by treatments, the body weight loss decreased linearly with the increasing of cis-9 C18:1 ratio. The effect of treatment on nutrient digestibility was limited, except a linear increase in ether extract and neutral detergent fiber digestibility with the increasing of cis-9 C18:1 ratio. There was a linear increase in the concentrations of plasma glucose, whereas the triglyceride and nonesterified fatty acid concentration decreased linearly with the increasing of cis-9 C18:1 ratio. As the cis-9 C18:1 ratio increased, the concentration of de novo fatty acids decreased quadratically, while the mixed and preformed fatty acids increased linearly. In conclusion, increasing cis-9 C18:1 ratio could increase production performance and decrease body weight loss by increasing nutrient digestibility, and the ratio had the most powerful beneficial effect on early lactating cows suggested by 72.7:27.3.

The colonization of microbes in the gut is key to establishing a healthy host-microbiome symbiosis for newborns. We longitudinally profiled the gut microbiome in a model consisting of 36 neonatal oxen from birth up to 2 months postpartum and carried out microbial transplantation to reshape their gut microbiome. Genomic reconstruction of deeply sequenced fecal samples resulted in a total of 3931 metagenomic-assembled genomes from 472 representative species, of which 184 were identified as new species when compared with existing databases of oxen. Single nucleotide level metagenomic profiling shows a rapid influx of microbes after birth, followed by dynamic shifts during the first few weeks of life. Microbial transplantation was found to reshape the genetic makeup of 33 metagenomic-assembled genomes (FDR < 0.05), mainly from Prevotella and Bacteroides species. We further linked over 20 million microbial single nucleotide variations to 736 plasma metabolites, which enabled us to characterize 24 study-wide significant associations (P < 4.4 x 10(-9)) that identify the potential microbial genetic regulation of host immune and neuro-related metabolites, including glutathione and L-dopa. Our integration analyses further revealed that microbial genetic variations may influence the health status and growth performance by modulating metabolites via structural regulation of their encoded proteins. For instance, we found that the albumin levels and total antioxidant capacity were correlated with L-dopa, which was determined by single nucleotide variations via structural regulations of metabolic enzymes. The current results indicate that temporal colonization and transplantation-driven strain replacement are crucial for newborn gut development, offering insights for enhancing newborn health and growth.

The dietary rumen-degradable starch (RDS) to rumen-degradable protein (RDP) ratio, denoted as the RDS-to-RDP ratio (SPR), has been proven to enhance in vitro rumen fermentation. However, the effects of dietary SPR in vivo remain largely unexplored. This study was conducted to investigate the effect of dietary SPR on lactation performance, nutrient digestibility, rumen fermentation patterns, blood indicators, and nitrogen (N) partitioning in mid-lactating Holstein cows. Seventy-two Holstein dairy cows were randomly assigned to three groups (24 head/group), balanced for (mean ± standard deviation) days in milk (116 ± 21.5), parity (2.1 ± 0.8), milk production (42 ± 2.1 kg/d), and body weight (705 ± 52.5 kg). The cows were fed diets with low (2.1, control), medium (2.3), or high (2.5) SPR, formulated to be isoenergetic, isonitrogenous, and iso-starch. The study consisted of a one-week adaptation phase followed by an eight-week experimental period. The results indicated that the high SPR group had a lower dry matter intake compared to the other groups (p < 0.05). A quadratic increase in milk yield and feed efficiency was observed with increasing dietary SPR (p < 0.05), peaking in the medium SPR group. The medium SPR group exhibited a lower milk somatic cell count and a higher blood total antioxidant capacity compared to other groups (p < 0.05). With increasing dietary SPR, there was a quadratic improvement (p < 0.05) in the total tract apparent digestibility of crude protein, ether extract, starch, neutral detergent fiber, and acid detergent fiber. Although no treatment effect was observed in rumen pH, the rumen total volatile fatty acids concentration and microbial crude protein synthesis increased quadratically (p < 0.05) as dietary SPR increased. The molar proportion of propionate linearly increased (p = 0.01), while branched-chain volatile fatty acids linearly decreased (p = 0.01) with increasing dietary SPR. The low SPR group (control) exhibited higher concentration of milk urea N, rumen ammonia N, and blood urea N than other groups (p < 0.05). Despite a linear decrease (p < 0.05) in the proportion of urinary N to N intake, increasing dietary SPR led to a quadratic increase (p = 0.01) in N utilization efficiency and a quadratic decrease (p < 0.05) in the proportion of fecal N to N intake. In conclusion, optimizing dietary SPR has the potential to enhance lactation performance and N utilization efficiency. Based on our findings, a medium dietary SPR (with SPR = 2.3) is recommended for mid-lactating Holstein dairy cows. Nevertheless, further research on rumen microbial composition and metabolites is warranted to elucidate the underlying mechanisms of the observed effects.

Domesticated herbivores are an important agricultural resource that play a critical role in global food security, particularly as they can adapt to varied environments, including marginal lands. An understanding of the molecular basis of their biology would contribute to better management and sustainable production. Thus, we conducted transcriptome sequencing of 100 to 105 tissues from two females of each of seven species of herbivore (cattle, sheep, goats, sika deer, horses, donkeys, and rabbits) including two breeds of sheep. The quality of raw and trimmed reads was assessed in terms of base quality, GC content, duplication sequence rate, overrepresented k-mers, and quality score distribution with FastQC. The high-quality filtered RNA-seq raw reads were deposited in a public database which provides approximately 54 billion high-quality paired-end sequencing reads in total, with an average mapping rate of ~93.92%. Transcriptome databases represent valuable resources that can be used to study patterns of gene expression, and pathways that are related to key biological processes, including important economic traits in herbivores.

BACKGROUND:The rumen of neonatal calves has limited functionality, and establishing intestinal microbiota may play a crucial role in their health and performance. Thus, we aim to explore the temporal colonization of the gut microbiome and the benefits of early microbial transplantation (MT) in newborn calves. RESULTS:We followed 36 newborn calves for 2 months and found that the composition and ecological interactions of their gut microbiomes likely reached maturity 1 month after birth. Temporal changes in the gut microbiome of newborn calves are widely associated with changes in their physiological statuses, such as growth and fiber digestion. Importantly, we observed that MT reshapes the gut microbiome of newborns by altering the abundance and interaction of Bacteroides species, as well as amino acid pathways, such as arginine biosynthesis. Two-year follow-up of those calves further showed that MT improves their later milk production. Notably, MT improves fiber digestion and antioxidant capacity of newborns while reducing diarrhea. MT also contributes to significant changes in the metabolomic landscape, and with putative causal mediation analysis, we suggest that altered gut microbial composition in newborns may influence physiological status through microbial-derived metabolites. CONCLUSIONS:Our study provides a metagenomic and metabolomic atlas of the temporal development of the gut microbiome in newborn calves. MT can alter the gut microbiome of newborns, leading to improved physiological status and later milk production. The data may help develop strategies to manipulate the gut microbiota during early life, which may be relevant to the health and production of newborn calves.

Chromium propionate (CrP) supplementation has the potential effects on mitigating metabolic stress on dairy cows, however, the effect of increased CrP supply on alleviating heat stress of mid-lactation cows is rarely evaluated. This study was conducted to evaluate the effect of CrP sup-plementation on lactation performance, nutrient digestibility, rumen fermentation patterns, and antioxidant status in dairy cows under heat stress. Sixty-four Holstein dairy cows in mid-lactation with similar parity (2.1 +/- 0.2), current milk production (40 +/- 1.4 kg/d), and days in milk (143 +/- 7.8 d) were randomly allocated to one of four treatments with a completely randomized design. After a 7-day adaptation period, cows were fed CrP at doses of 0, 4, 8, and 12 mg/d of Cr per head for 49 d. The average temperature humidity index (THI) was 77 during the experimental period. The average respiration rate and rectal temperature decreased quadratically (P < 0.01) with increasing CrP supplementation. Dry matter intake (DMI), milk yield, and milk lactose yield increased quadratically (P < 0.05) with increasing CrP supplementation, whereas 4% fat-corrected milk was not affected by treatments, and feed efficiency tended to decrease quadrati-cally (P = 0.07). The percentage of milk protein and lactose increased linearly (P = 0.05) with increasing CrP supplementation, whereas milk urea-N concentration and somatic cell count decreased quadratically (P < 0.01). Although total-tract apparent digestibility of dry matter, organic matter, crude protein, and ether extract was not affected by CrP supplementation, neutral detergent fiber digestibility increased quadratically (P = 0.01) with increasing CrP supplemen-tation. The concentrations of milk Cr and urinary Cr were not affected by CrP supplementation. Ruminal pH, the concentration of total VFA and ammonia-N, and the molar proportion of pro-pionate and butyrate were not affected by treatments, whereas the molar proportion of acetate increased quadratically (P < 0.01) with increasing CrP supplementation. The blood urea-N concentration decreased quadratically (P < 0.01) and the concentration of glutathione peroxidase and superoxide dismutase increased quadratically (P < 0.01) with increasing CrP supplementation, while the ratio of glucose to insulin and the concentration of glucose and malonaldehyde did not differ among treatments. In conclusion, CrP supplementation could increase milk yield in mid-lactation cows under heat stress by increasing DMI, reducing respiration rate and rectal temperature, and improving antioxidant status. The recommended dose of CrP is 4-8 mg/d of Cr per cow in hot weather.

【Objective】The purpose of this experiment was to explore the effects of different proportions of mixed silage of raw potato chips processing by product with rice straw（hereinafter referred to as “mixed storage”） instead of whole plant corn silage（hereinafter referred to as “silage”） on fattening performance, nutrient apparent digestibility, rumen fermentation parameters, blood biochemical indexes and economic benefits of Holstein bulls, so as to provide a theoretical basis for the use of potato processing by-products in cattle production.【Method】Sixty healthy Holstein bulls with similar body weight（（461.33 ± 33.47） kg） were randomly divided into four groups with 15 replicates in each group and one bull per replicate, including T20 group（concentrate +20% mixed silage + 80% silage）, T40 group（concentrate + 40% mixed silage + 60% silage）, T60 group（concentrate + 60% mixed silage + 40% silage）, and T80 group（concentrate + 80% mixed silage + 20% silage）. The ratio of concentrate to roughage and the composition of concentrate were the same in the experimental group. Adaptation and experimental periods lasted for 10 and 150 d,respectively.【Result】（1） there was no significant difference in average daily gain（ADG） of Holstein bulls with different proportions of mixed silage instead of whole plant maize silage（P＞0.05）. The dry matter intake（DMI） of T20 group was 4.30% higher than that of T40 group（P＜0.01）, 5.24% higher than that of T60 group（P＜0.01）, and 6.01% higher than that of T80 group（P＜0.01）. The feed gain ratio（F/G） of T40 group was the lowest, which was 4.08%（P＜0.01）, 3.14%（P＜0.05）, and 5.60%（P＜0.01） lower than that of T20, T60, and T80 groups, respectively.（2） Compared with T80 group, the apparent digestibility of dry matter（DM）, neutral detergent fiber（NDF）, acid detergent fiber（ADF） and ether extract（EE） of the first three groups were significantly increased（P＜0.05）. The apparent digestibility of crude protein（CP） of T20 group was significantly higher than that of T60 and T80 groups（P＜0.05）, but there was no significant difference between T20 group and T40 group（P＞0.05）.（3） The rumen pH, propionic acid and butyric acid contents were not affected by increasing the proportion of mixed storage（P＞0.05）. However, the concentrations of ammonia nitrogen（NH3-N） and total volatile fatty acids（TVFA） of T60 and T80 groups were significantly lower than those of T20group（P＜0.05）, and the content of acetic acid was significantly higher than that of T20 group（P＜0.01）. The ratio of acetic acid to propionic acid of T80 group was significantly higher than that of T20 and T40 groups（P＜0.05）.（4） Albumin（ALB） content of T20group was significantly higher than that of T60 and T80 groups（P＜0.05）. Urea nitrogen（UN） concentration of T80 group was significantly increased（P＜0.01）, 29.05%, 20.96% and 11.31% higher than that of T20, T40 and T60 groups, respectively. Glucose（Glu） concentration of T20 group was significantly higher than that of T60 and T80 groups（P＜0.01）, and there was no significant difference between T20 group and T40 group（P＞0.05）.（5） The economic benefit of T40 group was the highest（17.96yuan·head-1·d-1）, followed by T20（16.91 yuan·head-1·d-1）, T60（16.79 yuan·head-1·d-1） and T80（15.91 yuan·head-1·d-1）.【Conclusion】In conclusion, with the increase of the proportion of mixed silage instead of silage, the digestibility of nutrients,rumen fermentation and blood biochemical indexes would be affected to some extent. When replacing 40% whole plant maize silage,the production performance was the best and the economic benefit was the highest.

This experiment was conducted to study the effects of different treatment time and supplemental level of cellulase on in vitro nutrient degradation rate and rumen fermentation characteristics of wheat straw. A 4×4two-factor experimental design was used,including four cellulase treatment time（0,15,30 and 720 min）and four cellulase supplemental level（5 000,10 000,15 000 and 20 000 U/kg）,and the nutrient degradation rate and fermentation parameters were determined at different fermentation time（24 and 48 h）. The results showed as follows:1)with the cellulase treatment time increased,the in vitro fermentation dry matter degradation rate（DMD）,neutral detergent fiber degradation rate（NDFD）,acid detergent fiber degradation rate（ADFD）,acid detergent lignin degradation rate（ADLD）,hemicellulose degradation rate（HD）and cellulose degradation rate（CD）at 24 and 48 h were significantly increased（P＜0.05）except the HD at 24 h. With the cellulase supplemental level increased,the DMD,NDFD,ADFD,HD and CD at 24 h and HD at 48 h were linearly increased（P＜0.05）,and the ADLD at 24 h and DMD,NDFD,ADFD,ADLD and CD at 48 h were quadratically increased（P＜0.05）. There were no significant differences DMD,NDFD,ADFD,ADLD and CD between 10 000 and 20 000 U/kg cellulase supplemental level（P＞0.05）. 2)With the cellulase treatment time increased,the in vitro fermentation ammoniacal nitrogen（NH3-N）concentration was significantly increased（P＜0.05）,but the cellulase supplemental level had no significant effect on in vitro fermentation NH3-N concentration（P＞0.05）. With the cellulase treatment time increased,the in vitro fermentation total volatile fatty acid（TVFA）concentration at 48 h was significantly increased（P＜0.05）. 3)The 48 h gas production of30 min treatment time was significantly higher than that of other treatment time（P＜0.05）,and the theoretical maximum gas production and gas production rate of 30 and 720 min were significantly higher than those at0 min（P＜0.05）. With the cellulase supplemental level increased,the 48 h gas production,theoretical maximum gas production and gas production rate were quadratically increased（P＜0.05）. In conclusion,when cellulase supplemental level is 10 000 U/kg and treatment time is 30 min,it can improve the in vitro nutrient degradation rate of wheat straw,increase the NH3-H and VFA concentrations,improve gas production and gas production parameters,and improve in vitro rumen fermentation.[Chinese Journal of Animal Nutrition,2023,35（4）:2431-2442]

The aim of this study was to investigate the effect of low-protein diets supplemented with rumen-protected lysine (RPLys) and methionine (RPMet) on growth performance, rumen fermentation, blood biochemical parameters, nitrogen metabolism, and gene expression related to N metabolism in the liver of Holstein bulls. Thirty-six healthy and disease-free Holstein bulls with a similar body weight (BW) (424 ± 15 kg, 13 months old) were selected. According to their BW, they were randomly divided into three groups with 12 bulls in each group in a completely randomized design. The control group (D1) was fed with a high-protein basal diet (CP13%), while bulls in two low-protein groups were supplied a diet with 11% crude protein and RPLys 34 g/d·head + RPMet 2 g/d·head (low protein with low RPAA, T2) or RPLys 55 g/d·head + RPMet 9 g/d·head (low protein with high RPAA, T3). At the end of the experiment, the feces and urine of dairy bulls were collected for three consecutive days. Blood and rumen fluid were collected before morning feeding, and liver samples were collected after slaughtering. The results showed that the average daily gain (ADG) of bulls in the T3 group was higher than those in D1 (p < 0.05). Compared with D1, a significantly higher nitrogen utilization rate (p < 0.05) and serum IGF-1 content (p < 0.05) were observed in both T2 and T3 groups; however, blood urea nitrogen (BUN) content was significantly lower in the T2 and T3 groups (p < 0.05). The content of acetic acid in the rumen of the T3 group was significantly higher than that of the D1 group. No significant differences were observed among the different groups (p > 0.05) in relation to the alpha diversity. Compared with D1, the relative abundance of Christensenellaceae_R-7_group in T3 was higher (p < 0.05), while that of Prevotellaceae _YAB2003_group and Succinivibrio were lower (p < 0.05). Compared with D1 and T2 group, the T3 group showed an expression of messenger ribonucleic acid (mRNA) that is associated with (CPS-1, ASS1, OTC, ARG) and (N-AGS, S6K1, eIF4B, mTORC1) in liver; moreover, the T3 group was significantly enhanced (p < 0.05). Overall, our results indicated that low dietary protein (11%) levels added with RPAA (RPLys 55 g/d +RPMet 9 g/d) can benefit the growth performance of Holstein bulls by reducing nitrogen excretion and enhancing nitrogen efficiency in the liver.

Lycium barbarums are traditionally used as a homology of medicinal plants in China with a potent role in metabolism and immunomodulation. The current study was performed to explore the attenuation effect and microbiota regulation of Lycium barbarum polysaccharide (BLBP) on lipopolysaccharide (LPS)-induced intestine damage in mice. A total of 70 mice were randomly divided into five groups; negative control (GA), LPS (GB), both treated with an equal volume of normal saline, and BLBP treatment groups GC (100 mg/kg), GD (200 mg/kg), and GE (400 mg/kg) via gavage for 19 days. On Day 19, mice in groups GB, GC, GD, and GE were treated with 10 mg/kg LPS for 24 h and euthanized to collect intestine samples for pathological examination and microbiota sequencing. The results showed a non-significant difference in body weight gain among the five mouse groups; however, mice in the GC and GE groups showed decreased weight gain. An H&E examination revealed that the integrity of intestinal villi was destroyed by LPS, while BLBP supplement alleviated intestinal damage with an increase in villus height and a decrease in crypt depth. A total of over 59,000, 40,000, 50,000, 45,000, and 55,000 raw sequences were found in groups GA, GB, GC, GD, and GE, respectively. LPS challenge decreased alpha diversity indexes significantly ( p < 0.05), while a non-significant difference was found between different BLBP treatment groups and the GA group. A total of 8 phyla and 13 genera were found among five mouse groups, and BLBP partly restored the bacterial abundance in mice. LPS changed 282 metabolic pathways in KEGG L2, 77 metabolic pathways in KEGG L3, and 205 metabolic pathways in MetaCyc, respectively. The BLBP-supplemented groups, especially GE, showed reverse effects on those metabolic pathways. The current study revealed that BLBP can effectively decrease intestinal damage through the regulation of intestinal microbiota, which may provide new insights for the prevention of intestinal disease using food and medicine homologous of Lycium ruthenicum .

本试验旨在研究开食料中添加甜味剂与橙香剂对荷斯坦犊牛采食偏好、生长性能和血液指标的影响.试验采用双料槽设计,选取初生重[(38.80±0.36)kg]相近的健康荷斯坦犊牛60头,随机分为4组,分别为对照组、橙香剂组、甜味剂、橙香剂+甜味剂组,每组15头,对照组饲喂不含诱食剂的开食料,橙香剂组、甜味剂组、橙香剂+甜味剂组分别饲喂添加甜味剂、橙香剂、甜味剂+橙香剂的开食料.试验从犊牛3日龄开始,试验期为63 d.在试验第56天断奶后对犊牛开食料采食情况继续进行1周的追踪.结果显示:1)添加甜味剂和橙香剂对犊牛开食料采食量无显著交互作用(P＞0.05),但从整个饲养周期看,橙香剂使犊牛表现出了显著的采食偏好(P＜0.05).2)添加甜味剂和橙香剂对哺乳期犊牛体重和平均 日增重无显著交互作用(P＞0.05),但添加甜味剂显著增加了断奶后犊牛的平均日增重(P＜0.05).3)试验结束时,各组犊牛的体尺指标并没有表现出显著差异(P＞0.05).4)第28天时,添加甜味剂显著增加了犊牛血清白蛋白含量以及白球比(P＜0.05),有增加血清总蛋白含量的趋势(P=0.07),同时显著降低了血清球蛋白含量(P＜0.05);添加橙香剂显著增加了犊牛血清球蛋白含量(P＜0.05),有降低血清尿素氮含量的趋势(P=0.06).5)第28天时,添加橙香剂显著升高犊牛血清总抗氧化能力(P＜0.05),显著降低了血清谷草转氨酶活性(P＜0.05).6)第28天时,添加甜味剂有升高犊牛血清葡萄糖含量的趋势(P=0.05);第56天时,添加甜味剂有升高犊牛血清总胆固醇和甘油三酯含量的趋势(P=0.05).综上所述,在开食料中添加橙香剂使荷斯坦犊牛产生了采食偏好,虽未提高犊牛的生长性能,但有提高机体抗氧化能力和降低肝脏损伤的潜力;在开食料中添加甜味剂虽然未使荷斯坦犊牛产生采食偏好,但提高了断奶后犊牛的平均日增重,维持了体内糖、脂代谢稳态,并有提高机体免疫性能的潜力.

Background: The rumen of neonatal calves is underdeveloped and exhibits limited functionality during early life. Thus, the acquisition and colonization of microbes in the gut are key to establishing a healthy host-microbiome symbiosis for neonatal calves. Microbiome-linked health outcomes appear to be the consequences of individual strains of specific microbes. However, the temporal colonization of pioneering microbial strains and their linkages to the health and growth of neonatal calves are poorly understood.Results: To address this, we longitudinally profiled the gut microbiome of 36 neonatal calves from birth up to 2 months postpartum and carried out microbial transplantation (MT) to reshape their gut microbiome. Genomic reconstruction of deeply sequenced fecal samples resulted in a total of 3,931 metagenomic assembled genomes (MAGs), of which 397 were identified as new species when compared with existing databases of Bos taurus . Single nucleotide level metagenomic profiling shows a rapid influx of microbes after birth, followed by strong selection during the first few weeks of life. MT was found to reshape the genetic makeup of 33 MAGs (FDR<0.05), mainly from Prevotella and Bacteroides species. We further linked over 20 million microbial single nucleotide variations (SNVs) to 736 plasma metabolites, which enabled us to characterize 24 study-wide significant associations (P < 4.4×10−9) that identify the potential microbial genetic regulation of host immune and neuro-related metabolites, including glutathione and L-dopa. Our integration analyses further revealed that microbial genetic variations may influence the health status and growth performance of neonatal calves by modulating metabolites via structural regulation of their encoded proteins. For instance, we found that the albumin levels and total antioxidant capacity in neonatal calves were correlated with L-dopa, which was determined by SNVs via structural regulations of metabolic enzymes.Conclusions: The current results indicate that the temporal colonization of microbial strains and MT-induced strain replacement are integral in the development of the gut microbiome of neonatal calves and may help to develop strategies that can improve the health status and growth performance of neonatal calves.### Competing Interest StatementThe authors have declared no competing interest.* SNVs : single nucleotide variations MAGs : metagenomic assembled genomes MT : microbial transplantation SCFA : short-chain fatty acids COG : clusters of orthologous genes BCAA : branched-chain amino acid

Arginine can be metabolized into nitric oxide, polyamine, creatine, or agmatine, and each of those metabolites has several biological functions [...]

为研究脂肪来源对围产后期奶牛生产性能、瘤胃发酵、血液参数的影响,本试验选取胎次[(2.95±0.1)胎]、体况和上一胎次平均产奶量[(31.4±0.4)kg]相近的健康中国荷斯坦奶牛60头,采用完全随机试验设计,分为三组,每组20头奶牛,分别饲喂泌乳净能和粗蛋白质含量一致,但脂肪(酸)来源不同的日粮,三组分别为基础饲粮组(A组)、脂肪酸钙组(B组)、棕榈酸脂肪粉组(C组).试验期为母牛分娩当天(0 d)至产后21 d.试验结果表明:(1)干物质采食量:除泌乳天数10～12 d干物质采食量,B组较其他两组有下降的趋势(P=0.06)外,其他各阶段B组奶牛的干物质采食量显著低于A组和C组(P＜0.05),全期干物质采食量B组较A组和C组下降18.78％和14.56％(P＜0.01).(2)产奶量方面:整个试验期,B组产奶量均低于A组和C组(P＜0.05),但A组和C组差异不显著(P＞0.05),全期产奶量B组较A组和C组下降13.41％和12.48％(P＜0.05).(3)瘤胃发酵参数方面:血液β-羟丁酸浓度(BHBA)在产后7、14 d差异不显著(P＞0.05),产后21 dC组奶牛血液BHBA浓度较A组和B组下降16.44％和25.96％(P＜0.05),A组和B组差异不显著(P＞0.05);血液非酯化脂肪酸(NEEF)浓度在产后7 d和14 d差异不显著(P＞0.05),而在产后21 d C组较A组和B组下降31.49％和31.06％(P＜0.05);总胆固醇(TC)、甘油三脂(TG)、葡萄糖(GLU)、胰岛素生长因子(IGF-1)、牛瘦素(Lep)、尿素氮(BUN)检测产后0、7、14、21d组间差异不显著(P＞0.05).(4)血液肝脏指标代谢方面:在肝损代谢中谷丙转氨酶和谷草转氨酶虽然在产后0、7、21 d差异不显著(P＞0.05),但是产后14 d谷丙转氨酶C组较A组和B组下降28.98％和35.32％(P＜0.05),谷草转氨酶下降28.66％和10.62％(P＜0.05).A组和B组差异不显著.碱性磷酸酶、高密度脂蛋白胆固醇、低密度脂蛋白胆固醇产后0、7、14、21天差异不显著(P＞0.05).综上所述,在本试验条件下,饲粮中添加脂肪粉可提高围产后期奶牛采食量和产奶量,缓解奶牛体脂动员程度,提高血清GLU浓度,降低NEFA和BHBA浓度,缓解奶牛能量负平衡(NEB),并且效果好于脂肪酸钙组.

牛产业是畜牧业的重要组成部分,对于提高我国节粮型畜种比重、增加农民收入、调整居民膳食结构和改善人民生活具有重要意义.该文就肉牛业的发展历程及现状、肉牛主要饲养方式的简要介绍,并通过查阅相关资料,对影响肉牛育肥效果及胴体品质进行了研究分析,以期为肉牛产业的发展提供参考.