This study aims to determine the effects of dietary rosemary extract (RE) on meat quality, antioxidant capacity, fatty acid and amino acid compositions, and proteomic profile of duck breast muscle. Female Linwu ducks were allocated to 5 groups, giving basal diet supplemented with 0, 50, 150, 250, and 350 mg/kg RE for 56 d. Results showed that RE supplementation reduced average daily feed intake and feed-to-gain ratio of ducks, improved meat color, reduced drip loss, switched myofiber type, increased antioxidant capacity, and modulated amino acid and unsaturated fatty acid compositions in breast muscle. Subsequently, proteomic analysis comparing meat samples from the control and 250 mg/kg RE groups revealed the insulin signaling pathway and primary bile acid biosynthesis as major enriched pathways, identifying eight potential biomarkers. These findings suggest a novel approach to improve duck meat quality, and extend our knowledge of meat quality related markers.

Low protein digestibility causes intestinal flora imbalance, wet litter, and nitrogen pollution. The present study aimed to explore the optimal zymogram of exogenous acid protease (ACP), neutral protease (NEP), alkaline protease (ALP), and keratinase (KEA) in corn-soybean based diets for broilers. The hydrolysis performances of the four monocomponent proteases were presented by enzymatic hydrolysate gross energy (EHGE) and improved dry matter digestibility (IDMD), which were tested via the in vitro simulated digestion method. The optimal combination of the four proteases was predicted by the response surface method. Results showed that the optimal zymogram for 1 to 3-wk-old broiler diet was 1.80 U/g ACP, 2.30 U/g NEP, 29.30 U/g ALP, and 2.80 U/g KEA, and the EHGE and IDMD reached 94.65 Cal/g and 2.54%. The optimal zymogram for 4 to 6-wk-old broiler diet was 1.50 U/g ACP, 1.90 U/g NEP, 31.53 U/g ALP, and 3.10 U/g KEA, and the EHGE and IDMD reached 92.29 Cal/g and 2.47%. The performances of the predicted optimal zymogram were further verified by in vitro simulated digestion method. Collectively, the combined use of four proteases could improve the protein digestibility in broiler diets, which had better effect than monocomponent protease.

To study the effect of combined enzymes from Trichoderma reesei on growth performance, organ index, serum biochemical indices, and gut microbiota in broiler chickens, an experiment was conducted with 648 one-day-old AA broilers. The broilers were randomly divided into six groups. The control group was fed a corn-soybean meal basal diet, and the experimental groups were supplemented with different enzyme combinations. The experiment lasted 42 d. The results showed that from day 1-21, the average daily gain (ADG) of T1-T4 groups was higher than that of the control group (P = 0.005). From day 22-42, T2 had a higher ADG than T3 and T4 (P = 0.017). T1, T3, and T4 had a lower feed-to-gain ratio (F/G) than the control group from day 1-21 (P = 0.001).In terms of serum indices, T1-T5 had higher levels of triiodothyronine (T3), growth hormone (GH), and insulin-like growth factor-1 (IGF-1) at 21 and 42 days compared to the control group (P < 0.001), with some exceptions. T2-T5 had higher levels of superoxide dismutase (SOD), glutathione peroxidase (GSH-PX), and glutathione (GSH) at 21 and 42 days (P < 0.001), with some exceptions. For organ indices, T3 had a lower gizzard index and T5 had a higher gizzard index than the control group (P = 0.001), and T4 had a lower liver index than the control group (P = 0.041). Enzyme supplementation also changed the gut microbiota.In conclusion, all enzyme systems improved broiler growth performance from day 1-21. Only xylanase and the carbohydrase system from Trichoderma reesei enhanced growth from day 22-42. All enzyme systems enhanced antioxidant and immune capacities during the study period.

This study was designed to investigate the effects of dietary supplementation with different levels of DL-methionine (DL-Met) on growth performance, intestinal mucosal morphology and antioxidant capacity of Linwu ducks. The experiment was conducted to classify 330 healthy 49 days of age female Linwu ducks into 5 treatment groups with 6 replicates per treatment and fed diets with DL-Met levels of 2.5 g/kg, 3.0 g/kg, 3.5 g/kg, 4.0 g/kg, and 4.5 g/kg, respectively, for 21 days. The results showed that compared to the 2.5 g/kg group, the average daily weight gain (ADG) of Linwu ducks in the 3.5 g/kg group was significantly higher (P < 0.05), while the feed-to-gain ratio (FCR) of ducks in the 4.0 g/kg and 3.5 g/kg groups was similarly significantly decreased (P < 0.05). Additionally, the duodenal, jejunal, and ileum mucosal morphology was more structurally intact in the 3.5 g/kg and 4.0 g/kg groups, and the ratio of villus height to crypt depth (V/C) was significantly improved in the duodenum and ileum (P < 0.01). On the other hand, serum triglyceride (TG) and uric acid (BUN) levels were significantly (P < 0.05) decreased in the 3.5 g/kg group. Moreover, serum malondialdehyde (MDA) levels were significantly decreased (P < 0.05) in the 3.5 g/kg and 4.0 g/kg groups, while hepatic glutathione peroxidase (GPX) activity, GPX1, and glutathione S-transferase ɑ3 (GSTα3) mRNA expression levels were significantly increased (P < 0.05). Furthermore, hepatic total antioxidant capacity (T-AOC) activity was also significantly (P < 0.05) increased in the 3.5 g/kg group. In conclusion, dietary DL-Met supplementation could improve the growth performance of Linwu ducks by improving their redox status and intestinal mucosal morphology. Under the conditions of this experiment, the appropriate level of dietary Met supplementation for 49-70 days of age Linwu ducks is between 3.5 g/kg and 4.0 g/kg.

This study investigated the effects of dietary supplementation of indigenous dietary fiber (DF) sources with different solubilities on the growth performance, intestinal health, and gut microbiota in meat geese. A total of 400 meat geese at 17-d-old were randomly divided into 4 treatments with 10 replicates per treatment and 10 geese per replicate in a 28-d trial. The dietary treatments included a corn-soybean meal basal diet (BD), and BD supplemented with wheat bran as high soluble DF source (HS), alfalfa meal as medium soluble DF source (MS), or bamboo meal as low soluble DF source (LS). The results showed that dietary supplements of DF sources improved the growth performance of geese by improving final body weight (P = 0.010) and average daily weight gain (P = 0.003), and decreasing feed to gain ratio (P < 0.001). Among the DF source supplemented groups, HS treatment decreased the feed to gain ratio compared to LS treatment (P = 0.015). Next, HS and MS treatments decreased the levels of uric acid (P = 0.022) and triglyceride (P = 0.003) compared to BD and LS groups, and HS treatment decreased the high-density lipoprotein cholesterol level (P = 0.032) in serum compared to BD, LS, and MS groups. Additionally, dietary supplement of DF sources, especially the HS treatment improved the immune function of ileum and cecum by decreasing the levels of interlukin-10 level (P < 0.001) and interlukin-1β (P < 0.001), and increasing the level of secretory immunoglobulin A (P < 0.05) compared to BD, LS, and MS groups. Also DF sources supplements, especially the MS and HS treatments enhanced the antioxidant capacity of ileum and cecum by increasing activities of CAT (P < 0.001), SOD (P = 0.006 in ileum, P < 0.001 in cecum), and T-AOC (P < 0.001), but decreasing the MDA level (P < 0.001) compared to BD and LS groups. Furthermore, the length of ileum in BD group was shorter than DF source supplemented groups. And HS group had the longest ileum length (P = 0.010) and villus height (P = 0.001), and the most goblet cell number (P = 0.013) among all groups. Finally, by comparing the gut microbiota composition among BD, LS, and HS groups, HS treatment induced the enrichments of Butyricicoccus and Gemmiger, which were correlated with the improvements in the growth performance, lipid and fatty acid metabolisms, and intestinal condition. In conclusion, this study indicated that dietary supplementation of DF source, especially the high soluble DF source modulated the gut microbiota, enhanced the growth performance, nutrient metabolism, and intestinal health of meat geese. These findings suggested that highly soluble fiber sources might be preferable to use in geese production.

Oxidative stress is a major factor that limits the development of the poultry industry. Ferulic acid (FA) has an antioxidant effect in birds, but the mechanism is not fully understood. In this study, we stimulated oxidative stress in 28-day-old female Linwu ducks by lipopolysaccharide (LPS) and fed them a diet supplemented with FA for 28 days. Results showed that FA alleviated LPS-induced growth performance regression, oxidative stress, and microbiota imbalance in ducks. An integrated metagenomics and metabolomics analysis revealed that s_Blautia_obeum, s_Faecalibacterium_prausnitzii, s_gemmiger_formicilis, and s_Ruminococcaceae_bacterium could be the biomarkers in the antioxidant effect of FA, which interacted with dihydro-3-coumaric acid, L-phenylalanine, and 13(S)-HODE, and regulated the phenylalanine metabolism and PPAR signaling pathway. This study revealed the mechanism of the antioxidant effect of FA, which provided evidence of applying FA as a new antioxidant in commercial duck production.

This experiment was conducted to investigate the effects of different levels of organic trace elements replacing all inorganic trace elements on the deposition of copper（Cu）,iron（Fe）,manganese（Mn）and zinc（Zn）in liver,breast muscle,tibia and whole blood as well as intestinal development and morphology of Cherry Valley ducks aged from 1 to 42 days,and to determine the appropriate supplemental level of organic trace elements in diets. A total of 525 healthy Cherry Valley ducks of 1-day-old were randomly divided into 5groups with 7 replicates per group and 15 ducks per replicate. The control group（100% inorganic group）was provided with 100% trace elements in the form of inorganic salts at the recommended amount,while the four organic groups were provided with 25%,50%,75% and 100% Cu,Fe,Mn and Zn in form of hydroxy-methionine chelate at the recommended amount,respectively. The experiment lasted for 42 days. The experimental diets were divided into two stages（1 to 21 days of age in the early stage and 22 to 42 days of age in the late stage）,and all groups maintained the same nutrient levels except Cu,Fe,Mn and Zn. The results showed as follows:1)at 21 days of age,there were no significant differences in the contents of Cu,Fe,Mn and Zn in liver,breast muscle,tibia and whole blood among all groups（P＞0.05）. At 42 days of age,the contents of Cu and Zn in liver of meat ducks in 25% organic group were the lowest,and significantly lower than those in75% and 100% organic groups（P＜0.05）;the Fe content in tibia of meat ducks in 75% and 100% organic groups was significantly higher than that in the control group and 25% organic group（P＜0.05）;and the contents of Cu and Fe in whole blood of meat ducks in 100% organic group were the highest,and significantly higher than those in 25% organic group（P＜0.05）. 2)Compared with the control group,the relative weight of small intestine in four organic groups was increased but did not reach the significant difference level（P＞0.05）.There were no significant differences in villus height,crypt depth and ratio of villus height to crypt depth in duodenum,jejunum and ileum among all groups（P＞0.05）. In conclusion,Cherry Valley ducks aged from 1 to42 days fed diets supplemented with 50% to 100% Cu,Fe,Mn and Zn in form of hydroxy-methionine chelate at the standard recommended amount can increase the deposition of trace elements in tissues,improve intestinal morphology and promote intestine development. Considering the production cost,it is recommended that Cherry Valley ducks aged from 1 to 42 days should be supplemented with 50% organic trace elements of the standard recommended amount.[Chinese Journal of Animal Nutrition,2023,35（4）:2316-2325]

本试验旨在评定14种不同来源的稻谷对鹅的代谢能及主要营养物质表观利用率,建立稻谷的代谢能预测方程.采集来自江西、广西、广东、湖南和安徽等5个省区的14种稻谷作为鹅的饲料原料.选用200日龄、身体健康、体重[(5.30±0.43)kg]相近的武冈铜鹅公鹅24只,随机分为4组(每组6个重复,每个重复1只),每组对应1种待测稻谷,共进行4期代谢试验.采用强饲法进行代谢试验,每只鹅强饲80 g待测稻谷.结果表明:1)14种稻谷的总能(GE)分别为 15.75、15.94、16.08、15.60、16.07、15.92、16.00、16.60、16.02、15.91、16.47、16.09、16.06和15.53 MJ/kg,平均值为16.00 MJ/kg.粗蛋白质(CP)、粗脂肪(EE)、粗纤维(CF)、中性洗涤纤维(NDF)、酸性洗涤纤维(ADF)、粗灰分(Ash)、钙(Ca)、总磷(TP)、支链淀粉(AP)、直链淀粉(AM)、可溶性纤维(SDF)和不可溶性纤维(IDF)含量平均值分别为7.19％、2.70％、6.77％、19.01％、7.39％、3.76％、0.07％、0.25％、41.40％、18.73％、5.51％和 14.15％.2)14 种稻谷在鹅中的GE利用率、表观代谢能(AME)和真代谢能(TME)平均值分别为79.47％、12.71 MJ/kg和13.34 MJ/kg.3)鹅对稻谷CP、CF、EE、SDF和IDF表观利用率平均值分别为60.58％、11.91％、60.54％、61.69％和 27.91％..4)通过回归分析建立了 AME、TME 的多元回归预测方程:AME=1.605GE-4.202NDF-13.293(R2=0.341,P=0.039),TME=1.626GE-4.400NDF-12.259(R2=0.385,P=0.028).由此可见,武冈铜鹅对14种不同来源稻谷的代谢能存在差异,可利用稻谷的主要营养物质含量建立其代谢能的预测方程.

试验旨在比较芷江鸭与主要兼用型鸭种(临武鸭、高邮鸭、大余鸭和靖西大麻鸭)外貌特征、体重体尺、屠宰性能、胸肌常规营养成分和蛋品质的差异,为芷江鸭品种资源开发利用提供参考依据.

This study aimed to explore the effects of hydrolyzed Tara tannic acid on growth performance,serum antioxidant capacity and immune capacity of weaned piglets,and provide evidences for the utilization of hydrolyzed Tara tannic acid in weaned piglet production. A total of 200 weaned piglets at 28 days of age with similar weight were randomly divided into 5 groups. Each group had 4 replicates,and each replicate had 10piglets. Control group was fed a basal diet,and 4 experimental groups were fed the basal diet supplemented with 250,500,750 and 1 000 g/t hydrolyzed Tara tannic acid,respectively. The experiment lasted 28 days.The feed intake and diarrhea situation were reported daily. After the experiment,piglets were weighted,and one piglet from each replicate was selected to collect blood for the measurements of antioxidant and immune parameters. The results showed as follows:1)compared with the control group,diets supplemented with 750 g/t hydrolyzed Tara tannic acid significantly increased final weight and average daily gain（P＜0.01）,but had no significant effects on average daily feed intake,ratio of feed to gain,diarrhea rate and diarrhea index（P ＞0.05）. 2)Compared with the control group,hydrolyzed Tara tannic acid significantly increased serum activity of catalase（P＜0.01）;250,500,and 750 g/t hydrolyzed Tara tannic acid significantly increased serum activity of superoxide dismutase（P＜0.01）,and decreased serum content of malonaldehyde（P＜0.01）;1 000 g/t hydrolyzed Tara tannic acid significantly increased serum activity of glutathion peroxidase（P＜0.01）;500,750 and 1 000 g/t hydrolyzed Tara tannic acid significantly increased the serum total antioxidant capacity（P＜0.01）. Furthermore,hydrolyzed Tara tannic acid significantly increased serum contents of immunoglobulin A and complement C4（P＜0.01）. In conclusion,supplementation of hydrolyzed Tara tannic acid in diet can increase the growth performance,serum antioxidative capacity and immune capacity of weaned piglets.[Chinese Journal of Animal Nutrition,2023,35（4）:2175-2183]

本试验旨在研究不同饲粮色氨酸(Trp)水平对攸县麻鸭生长性能、血清生化和抗氧化指标的影响,以确定6～12周龄攸县麻鸭色氨酸需要量.试验选取42日龄体重相近的攸县麻鸭468羽,随机分成6组,每组6个重复,每个重复13羽.在赖氨酸水平为0.85％条件下,各组试验饲粮中色氨酸水平分别为0.14％、0.15％、0.16％、0.17％、0.18％和0.19％.试验期为42 d.结果表明:1)0.16％和0.17％色氨酸水平组的末重显著高于0.14％、0.15％、0.18％和0.19％色氨酸水平组(P＜0.05).0.15％、0.16％、0.17％和0.18％色氨酸水平组的平均日增重(ADG)显著高于0.14％色氨酸水平组(P＜0.05).0.16％和0.17％色氨酸水平组的料重比(F/G)显著低于0.14％、0.15％、0.18％和0.19％色氨酸水平组(P＜0.05).2)0.16％和0.17％色氨酸水平组血清尿酸(UA)含量显著低于0.14％、0.15％和0.19％色氨酸水平组(P＜0.05).0.16％、0.17％、0.18％和0.19％色氨酸水平组血清甘油三酯(TG)含量显著低于0.14％色氨酸水平组(P＜0.05).0.16％、0.17％、0.18％和0.19％色氨酸水平组血清游离色氨酸含量显著高于0.14％和0.15％色氨酸水平组(P＜0.05).3)0.16％、0.17％、0.18％和0.19％色氨酸水平组血清丙二醛(MDA)含量显著低于0.14％色氨酸水平组(P＜0.05).0.16％、0.17％、0.18％和0.19％色氨酸水平组血清谷胱甘肽过氧化物酶(GSH-Px)活性显著高于0.14％色氨酸水平组(P＜0.05).4)回归分析显示,以末重、ADG、F/G及血清UA、TG含量和GSH-Px活性为评价指标,6～12周龄攸县麻鸭饲粮适宜色氨酸水平为0.166％～0.178％.由此可见,在本试验条件下,饲粮色氨酸水平为0.16％时即可满足6～12周龄攸县麻鸭生产需要,但为获得较佳血清生化指标和抗氧化能力,建议6～12周龄攸县麻鸭饲粮色氨酸水平为0.166％～0.178％.

本文旨在研究不同比例支链氨基酸(BCAAs)对28～63日龄攸县麻鸭盲肠微生物菌群的影响.采用单因子设计,选用28日龄健康、体质量相近的攸县麻鸭504羽,随机分为6个处理,每处理6个重复,每重复14羽,分别饲喂不同比例支链氨基酸(BCAAs)饲粮.其中BCAAs饲粮中亮氨酸、缬氨酸、异亮氨酸按质量比m(Leu):m(Val):m(Ile)分为1:0.4:0.3(MA组)、1:0.5:0.4(MB组)、1:0.6:0.5(MC组)、1:0.7:0.6(MD组)、1:0.8:0.7(ME组)和1:0.9:0.8(MF组)共6组.试验期35 d,试验结束当天,分别从每重复中选择1羽试鸭采集盲肠内容物,利用16S rDNA测序技术分析盲肠微生物结构和菌群多样性.结果显示:1)6个组共有的OTU数目344,仅MD组存在1个特有的OTU.2)在门水平上,核心菌群是拟杆菌门Bacteroidetes、厚壁菌门Firmicute和变形菌门Proteobacteria;在属水平上,拟杆菌属Bacteroides和脱硫弧菌属Desulfovibrio为优势菌属.3)6组比较发现,MD组变形菌门丰度显著高于ME组(P<0.05),MF组放线菌门丰度显著高于MA组(P<0.05).4)6个试验组间Ace指数和Chao1指数的差异不显著,MF组的Shannon指数显著大于MC组(P<0.05),MC组的Simpson指数极显著大于MF组(P<0.01)和显著大于MA组(P<0.05).综上,63日龄攸县麻鸭盲肠的核心菌群是拟杆菌门、厚壁菌门、变形菌门,饲粮BCAAs比例显著影响变形菌门及放线菌门,当m(Leu):m(Val):m(Ile)=1:0.9:0.8时,攸县麻鸭盲肠微生物物种多样性最高.

Introduction This study aimed to investigate the effects of organic trace elements chelated with hydroxy methionine (OTE-HM) in diets, which substituted inorganic trace elements, on laying performance, egg quality, blood microelement content, antioxidant capacity and immune function of laying ducks. Methods A total of 300 healthy laying ducks at age of 30 wk were randomly divided into 5 treatments and 10 ducks per replicate. The treatments included a control group (CON) which was served with basal diet supplemented with 20 mg/kg Cu, 50 mg/kg Fe, 70 mg/kg Mn, and 70 mg/kg Zn in inorganic form, and 4 OTE-HM treated groups (OTE-HM25, OTE-HM50, OTE-HM75, OTE-HM100) which were served with basal diets supplemented with OTE-HM providing trace elements (combination of Cu, Fe, Mn, Zn) at 25%, 50%, 75% and 100% of the commercial levels, respectively. Results Results showed that substitution of inorganic trace elements with OTE-HM did not affect egg production, qualified egg rate, average egg weight, average daily egg mass, average daily feed intake, or feed per kg egg of laying ducks ( P > 0.05). Dietary with OTE-HM did not influence eggshell strength, eggshell thickness, egg shape index, eggshell ratio, yolk ratio, albumen ratio, albumen height, and Haugh unit of the sampled eggs of ducks ( P > 0.05), but increased the yolk color, compared with dietary with inorganic trace elements ( P< 0.01). Moreover, the blood content of Cu of the laying ducks was significantly increased by OTE-HM compared with that in CON ( P< 0.001), but the other elements in laying duck blood were not different among treatments ( P > 0.05). OTE-HM (75% and 100%) significantly increased serum activities of glutathione peroxidase and Cu-Zn superoxide dismutase, and decreased serum content of malonaldehyde of laying ducks compared with those in CON ( P< 0.05). OTE-HM (50%, 75%, and 100%) significantly increased the serum contents of immunoglobulin G and immunoglobulin A of laying ducks compared with those in CON ( P< 0.05). Discussion Collectively, replacing inorganic trace elements with 50% and 75% OTE-HM in diets did not influence the laying performance or egg quality, but improved trace element efficacy, antioxidant capacity and immune function of the laying ducks.

本试验旨在研究饲粮中添加亚硒酸二葡萄糖酯对7～35日龄临武鸭生长性能、免疫器官指数、血清生化和抗氧化指标的影响.试验采用单因子试验设计,选取300只7日龄体况健康的临武鸭,随机分为5组,每组6个重复,每个重复10只鸭.对照组(Ⅰ组)饲喂基础饲粮,不额外补充硒源;试验组(Ⅱ、Ⅲ、Ⅳ、V组)分别在基础饲粮中添加0.10、0.20、0.30和0.40 mg/kg的亚硒酸二葡萄糖酯(以硒计).试验期28 d.结果表明:1)饲粮中添加亚硒酸二葡萄糖酯对7～35日龄临武鸭生长性能和免疫器官指数无显著影响(P＞0.05).2)V组血清甘油三酯含量显著低于Ⅰ、Ⅲ和Ⅳ组(P＜0.05).V组血清硒含量显著高于Ⅰ、Ⅱ、Ⅲ和Ⅳ组(P＜0.05).3)V组血清谷胱甘肽过氧化物酶活性和谷胱甘肽含量显著高于Ⅰ和Ⅱ组(P＜0.05).由此可见,饲粮中添加亚硒酸二葡萄糖酯对7～35日龄临武鸭生长性能和免疫器官指数无不良影响,但可降低血清甘油三脂含量,并能提高机体抗氧化能力.综合各项指标,7～35日龄临武鸭饲粮中亚硒酸二葡萄糖酯适宜添加水平为0.40 mg/kg(以硒计).

本试验旨在研究饲粮支链氨基酸(BCAAs)比例对29～63日龄攸县麻鸭生长性能、血清生化指标和肠道发育的影响,以确定其饲粮适宜BCAAs比例.试验选取28日龄健康、体重相近的攸县麻鸭公鸭504只,随机分为6组,每组6个重复,每个重复14只.饲粮BCAAs维持总量不变,各组(1～6组)中亮氨酸(Leu)∶缬氨酸(Val)∶异亮氨酸(Ile)比例分别为1∶0.4∶0.3、1∶0.5∶0.4、1∶0.6∶0.5、1∶0.7∶0.6、1∶0.8∶0.7 和 1∶0.9∶0.8,其他营养成分水平保持一致.试验期35 d.结果显示:1)饲粮不同BCAAs比例对试验鸭平均日采食量无显著影响(P＞0.05).1组末重和平均日增重显著低于其他5组(P＜0.05).4组的料重比最低,且显著低于1和2组(P＜0.05).2)4、5和6组血清中葡萄糖含量显著低于1和2组(P＜0.05);血清中尿酸含量随饲粮Val和Ile比例增加呈先降低后升高趋势,其中4组血清中尿酸含量最低,显著低于1、5和6组(P＜0.05);4和5组血清中甘油三酯含量显著低于1和2组(P＜0.05);3、4和5组血清中游离脂肪酸含量显著低于1、2和6组(P＜0.05).3)不同饲粮BCAAs比例对试验鸭十二指肠、空肠和回肠的单位长度重量以及相对重量均无显著影响(P＞0.05).由此可见,饲粮中BCAAs总量为3.76％时,其比例在1∶0.6∶0.5～1∶0.7∶0.6,29～63日龄攸县麻鸭生长性能和血清生化指标较优.

本试验旨在研究饲粮精氨酸水平对8～35日龄临武鸭生长性能及血清生化、抗氧化和免疫指标的影响.选用7日龄雌性临武鸭560只,随机分为5个组,每组7个重复,每重复16只.各组饲粮精氨酸水平分别为0.9％、1.0％、1.1％、1.2％和1.3％,其他营养水平保持一致.试验期28 d.结果表明:1)饲粮精氨酸水平对8～35日龄临武鸭末重、平均日增重和平均日采食量均无显著影响(P＞0.05).1.1％和1.2％精氨酸水平组的料重比显著低于0.9％精氨酸水平组(P＜0.05).2)饲粮精氨酸水平对8～35日龄临武鸭血清葡萄糖、尿酸、尿素氮、甘油三酯、总胆固醇、高密度脂蛋白胆固醇、低密度脂蛋白胆固醇含量和天门冬氨酸氨基转移酶活性均无显著影响(P＞0.05).1.2％和1.3％精氨酸水平组的血清碱性磷酸酶活性显著高于0.9％、1.0％和1.1％精氨酸水平组(P＜0.05),1.0％、1.1％、1.2％和1.3％精氨酸水平组的血清丙氨酸氨基转移酶活性显著高于0.9％精氨酸水平组(P＜0.05).3)饲粮精氨酸水平对8～35日龄临武鸭血清丙二醛含量、总抗氧化能力及谷胱甘肽过氧化物酶、超氧化物歧化酶活性均无显著影响(P＞0.05).4)饲粮精氨酸水平对8～35日龄临武鸭血清总蛋白、白蛋白、球蛋白、免疫球蛋白A、免疫球蛋白G、免疫球蛋白M含量及白球比均无显著影响(P＞0.05).1.1％、1.2％和1.3％精氨酸水平组的血清一氧化氮含量显著高于0.9％精氨酸水平组(P＜0.05).由此可见,饲粮适宜精氨酸水平降低了 8～35日龄临武鸭的料重比,提高了血清NO含量.通过二次曲线回归模型分析,8～35日龄临武鸭饲粮适宜精氨酸水平为1.15％～1.20％.

本试验旨在研究饲粮不同能量和蛋白质限饲水平对育成期蛋鸭生长性能、生殖器官发育、血清生殖激素含量及产蛋性能的影响,以筛选出攸县麻鸭育成期理想的限饲方法.选择9周龄攸县麻鸭母鸭360只,随机分为4组,每组9个重复,每个重复10只鸭.各组饲喂不同限饲饲粮7周后均改饲相同商品料至72周龄.限饲期间对照组(Ⅰ组)饲喂代谢能11.08MJ/kg、蛋白质15％的基础饲粮,3个试验组(Ⅱ、Ⅲ、Ⅳ组)分别饲喂在对照组饲粮基础上同时降低代谢能和蛋白质水平5％、10％和15％的试验饲粮.结果表明:1)与Ⅰ组相比,降低饲粮能量和蛋白质水平显著提高了平均日采食量(P＜0.05),显著降低了平均日增重(P＜0.05),但对末重无显著影响(P＞0.05).2)随饲粮能量和蛋白质水平降低,试验鸭优势卵泡数、优势卵泡重、卵巢重和卵巢指数显著下降(P＜0.05),而其对输卵管各指标均无显著影响(P＞0.05).各组间血清中雌二醇、孕酮和促黄体生成素含量均无显著差异(P＞0.05).3)饲粮能量和蛋白质水平降低5％～15％,可显著提高产蛋期平均蛋重(P＜0.05).Ⅱ和Ⅲ组产蛋率＞80％天数显著高于Ⅰ组(P＜0.05).综上所述,在自由采食条件下,饲粮能量和蛋白质水平降低5％～15％,育成期攸县麻鸭虽平均日采食量增加,平均日增重降低,性成熟延迟,但可提高产蛋性能.综合考虑全期产蛋性能和饲料成本等因素,建议育成期攸县麻鸭饲粮营养水平以降低5％～10％为宜.

After the legislative ban on the utilization of antibiotics in animal feed, phytochemical substances gained increasing attention as alternatives to antibiotics because of their bioactivities and safety for animals. The present study aimed to investigate the influence of dietary rosemary extract (RE) on growth performance, meat quality, serum biochemistry, antioxidant and immune capacities, and gut microbiota composition of broilers. By exploring connections among RE, physiological characteristics of broilers, and key microbiota, we sought to provide evidence for the utilization of RE in poultry feed. A total of 280 1-d-old female AA broilers were randomly separated into five groups, and were fed a basal diet supplemented with 0, 250, 500, 750, and 1,000 mg/kg of RE, respectively. Results showed that with regard to growth performance, both 500 and 750 mg/kg RE reduced the broiler feed-to-gain ratio from 1 to 21 d (P = 0.018). Regarding meat quality, all compositions of dietary RE reduced cooking loss of breast muscle (P < 0.01), and 500 and 1,000 mg/kg RE reduced the cooking loss of thigh muscle (P = 0.045). Regarding serum biochemical indexes, 500 mg/kg RE reduced ALB, TCHO, HDL-C, and LDL-C, and 750 mg/kg RE reduced GLU, TP, ALB, UA, TG, TCHO, HDL-C, and LDL-C (P < 0.01). Regarding antioxidant and immune capacities, 250, 500, 750, and 1,000 mg/kg RE increased T-AOC, GSH-Px, SOD, CAT, IL-2, IgA, IgG, and IgM levels (P < 0.01), and decreased serum MDA level (P < 0.01). RE at 750 mg/kg showed similar effects on growth performance, meat quality, and antioxidative and immune capacities, but a better influence on serum biochemical indexes of broilers compared with 500 mg/kg. Further analysis was conducted to investigate the effect of 750 mg/kg dietary RE on the gut microbial composition of broilers, and the results showed that 750 mg/kg RE reduced the relative abundance of g_Lachnoclostridium, g_Escherichia_Shigella, and g_Marvinbryantia (P <0.05, LDA score >2), which were negatively correlated to antioxidative and immune-associated parameters (P < 0.05). In conclusion, 750 mg/kg dietary RE was shown to have certain beneficial effects on growth performance and meat quality, and hypolipidemic and hypoglycemic effects on broilers. Furthermore, dietary RE improved antioxidant and immune capacities, which was partially attributed to the reduced abundance of certain pathogenic bacteria in broilers.