This study evaluated the effects of organic acids (OA), Campylobacter jejuni (CJ) inoculation, and their combination on cecal CJ colonization, intestinal morphology, cecal microbiota, and broiler performance. A 4 & times;2 factorial arrangement in a randomized complete block design was used, with pen location as the blocking factor. A total of 2240 Ross 708 males were allocated into 64 pens (8 replicates/treatment; 35 birds/pen). Pens received one of four water treatments: control (water), intermittent OA-A (2 mL/L; days 0-5, then 1 day/week), continuous OA-A (2 mL/L), or continuous OA-B (2.6 mL/L), where OA-A and OA-B are citric acid-based water acidifiers. Birds were gavaged on day 21 with either phosphate buffered saline or CJ (10(4) CFU/mL). CJ enumeration was conducted on days 23, 28, 35, and 42. Duodenum, jejunum, and ileum samples were collected on day 42 for villus height, crypt depth, and villus-to-crypt ratio (V:C). Cecal contents were collected for microbiota analysis, and body weights and feed intake were recorded on days 0, 13, 27, and 41. Data were analyzed using ANOVA (GLIMMIX, SAS v9.4) and cecal microbiota data in R. OA supplementation did not reduce cecal CJ colonization (P > 0.05). No interaction effects were found for intestinal morphology, but CJ-inoculated birds had deeper jejunal crypts (P = 0.0018) and reduced ileal villus height and V:C (P = 0.0134 and 0.0003). CJ altered microbiota alpha-and beta-diversity, but no interaction effects were observed. Broilers receiving citric acid-based OA-A had higher body weights than control and OA-B birds on day 41 (P = 0.0029). In conclusion, OA did not reduce CJ colonization or improve gut morphology but improved final body weight.
The objective of the present study was to evaluate the impact of adding hydroponic green forage made from corn and oats on productive variables and gut microbiota in broiler chickens. Two hundred Ross 308 broiler chickens were used. Birds were randomly allocated to four dietary treatments with five replicates per treatment, as follows: (Control), basal diet; (BD + HGMF), basal diet supplemented with hydroponic green corn forage; (BD + HGMOF), basal diet supplemented with hydroponic green corn and oat forage; and (BD + HGOF), basal diet supplemented with hydroponic green oat forage. Treatments that included hydroponic forage were offered fresh, for a period of 4 h, to simulate grazing from 09:00 to 13:00 h, in outdoor pens with 1 h of prior feed restriction. The results show that, at the finishing stage, birds in the control treatment showed greater weight gain with 2.52 kg, showing differences with the treatments that were offered some type of hydroponic forage in the diet (P < 0.05); however, feed consumption did not show differences (P > 0.05) between the control treatment and HGMF with average consumption of 3.81 and 3.40 kg respectively, while birds that were provided some type of hydroponic forage did not show significant differences. Regarding the FCR, carcass yield, and weight of the meat pieces, no differences were found between treatments (P > 0.05). Concerning gut microbiota quantification, hydroponic forage supplementation did not significantly influence fecal total aerobic mesophiles (TAM) and Enterobacteriaceae counts in the different treatments.
This study evaluated the effect of early growth (EG) - shifts of gain from the pubertal phase (g(2)) to the prepubertal phase (g(1)) - and pubertal growth rate (b(2)) on development, feed efficiency, carcass composition, and reproductive performance of broiler breeder females. Two-hundred-eighty-eight Ross 308 pullets were randomly assigned to twelve BW growth trajectories and fed using a precision feeding system from 0 to 60 wk of age. A 3-phase Gompertz model fit to the recommended BW target of Ross 308 breeders was utilized, describing growth in phase 1, 2, and 3 (prepubertal, pubertal, and postpubertal, respectively). To design 12 growth trajectory treatments in a 6 & times; 2 factorial arrangement, six levels of the gain coefficients and two levels of the b(2) coefficient were used. The six continuous EG shifts were in 10% increments: -10%, 0% (Ross 308 standard), 10%, 20%, 30%, and 40%. For each EG treatment, the given gain (kg) as percentage of g(2) was shifted to g(1). The 0% shift treatment used the coefficients g(1) and g(2) that described the breeder recommended target BW. The b(2) factor had two levels: Standard, where b(2) was 100% of the estimated standard pubertal growth rate from the breeder recommended pubertal phase (Standard b(2)); and 50% faster, where b(2) was increased 50 percent (b(2) 150%). Weekly BW and carcass composition were analyzed using three-way ANOVA (b(2), EG, and age as fixed sources of variation). Analysis of covariance was conducted on the remaining dependent variables with b(2) as fixed effect, EG and age as continuous fixed effects. Bird BW followed the target BW trajectories for most of the study duration, as ADFI differed depending on the feed amount required to achieve the respective BW trajectories. Advancing EG increased breast fleshing score and pubic bone space and decreased the number of juvenile primary wing feathers during rearing (P < 0.05). Carcass fat percent increased with advanced EG after 4 wk of age, but this difference was not observed from 20 wk onward. Neither EG nor b(2) significantly affected egg production (P > 0.05). Feed per chick produced decreased with advanced EG only when b(2) was increased (b(2) 150%; P < 0.05). In conclusion, early pullet growth increased mostly muscle and skeletal characteristics, whereas reproduction efficiency was increased by advanced EG only when pubertal growth rate was also increased.
This study aimed to enhance the egg quality of native Iranian chickens through a crossbreeding program using White Leghorn (WL) as the dam line and Marandi (MA) as the parental line to produce crossbred offspring (MA x WL). Various egg quality parameters were assessed during the experiment. Significant differences were observed in egg quality traits between WL and MA, with WL demonstrating superior performance in most traits (except shell percentage and egg shape index) compared to MA (P < 0.05). Notably, the MA x WL exhibited significantly improved performance in most studied traits compared to MA. Negative heterosis was observed for albumen height and Haugh unit, which showed similar values in MA and MA x WL. Furthermore, MA x WL resembled WL more closely than MA in terms of egg dimensions, shell weight, and yolk weight (P < 0.05). Overall, this study suggests that crossbreeding can enhance the egg quality of native chickens by leveraging the expression of relevant WL genes in the crossbreds. Additionally, the adaptability of MA to local environmental conditions may be partially inherited by MA x WL, warranting further investigation in subsequent studies.
A decline in feather coverage in chickens due to the presence of the naked neck (Na) gene may alter sulfur amino acid requirements under high ambient temperatures. The present study aimed to determine the growth performance and carcass traits of naked neck (NaNa; Nana) and normally feathered (nana) genotypes when fed diets supplemented with different levels of methionine under hot environmental conditions. A three-factorial experimental design (3 & times; 3) was used, comprising three genotypes (NaNa, Nana, nana) and three dietary methionine supplementation levels (0.30, 0.35, and 0.40%). A total of 108 male chicks aged 4 weeks (36 birds per genotype) were randomly assigned to three dietary methionine levels in individual cages (12 birds per subgroup). Dietary methionine level had no significant effect on body weight, body weight gain, or feed conversion ratio. However, increasing methionine levels significantly (p <= 0.01) increased breast muscle percentage, dressing percentage, and the relative weight of edible parts. On the other hand, the relative weight of abdominal fat decreased significantly (p <= 0.01) with increasing dietary methionine levels. Additionally, naked neck genotypes (NaNa; Nana) had significantly (p <= 0.01) lower abdominal fat percentages compared to the normally feathered genotype (nana). A significant interaction between genotype and methionine level was detected for relative weight of breast muscles, with a favorable effect of the Na gene observed at higher dietary methionine levels. Introducing the naked neck gene into chicken populations fed diets supplemented with higher levels of methionine is highly recommended under hot environmental conditions.
