Effect of First Feed Intake Time on Broiler Performance and Carcass Traits

Feeding strategy and prebiotic supplementation: Effects on immune responses and gut health in the early life stage of broiler chickens

This study aimed to investigate the effects of early or late feeding strategies and prebiotic, on immune responses and gut health during the early life stage of broiler chickens. A total of 240 day-old male broiler chicks were used in a 2 × 3 factorial arrangement of treatments that comprised 2 feeding strategies (early or late) and 3 levels of prebiotic (0, recommended dosage or three times the recommended dosage) in a completely randomized design with 4 pen replicates and 10 broilers per each. Compared to broiler chickens that had early access to feed, delayed access to feed resulted in an increased population of Escherichia coli and a decreased population of Lactobacillus spp. and Bifidobacterium spp. in the ileum (P < 0.05). Additionally, delayed access to feed led to a decrease in villus height, crypt depth, villus height: villus width ratio, goblet cell density, and mucin 2 gene expression in the ileum (P < 0.05). The supplementation of prebiotics in both the late and early feeding strategy groups resulted in increased villus height, crypt depth, goblet cell density, mucin 2 gene expression, and antibodies against Infectious Bursal Disease (IBD). Additionally, it led to an improvement in the foot web thickness index (P < 0.05). Furthermore, it resulted in a significant decrease in the population of Escherichia coli, while the populations of Lactobacillus spp. and Bifidobacterium spp. in the ileum were significantly increased (P < 0.05). Therefore, this study suggests that incorporating prebiotics in the starter diet can effectively enhance immune responses and promote gut health, regardless of the feeding strategy (early or late). In conclusion, this study demonstrates the potential benefits of incorporating prebiotics into poultry diets to alleviate the detrimental effects of delayed access to feed and improve gut health during the early life stage of broiler chickens.

Delayed access to feed affects broiler small intestinal morphology and goblet cell ontogeny

Broilers are often deprived of feed and water for up to 48 h after hatch. This delayed access to feed (DAF) can inhibit small intestine development. The objective of this study was to determine the effects of DAF on small intestinal morphology, mRNA abundance of the goblet cell marker Muc2 and absorptive cell marker PepT1, and the distribution of goblet cells in young broilers. Cobb 500 chicks, hatching within a 12-h window, were randomly allocated into 3 groups: control with no feed delay (ND), 24-h feed delay (DAF24), and 36-h feed delay (DAF36). Morphology, gene expression, and in situ hybridization analyses were conducted on the duodenum, jejunum, and ileum at 0, 24, 36, 72, 120, and 168 h after hatch. Statistical analysis was performed using a t test for ND and DAF24 at 24 h. A 2-way ANOVA and Tukey's HSD test (P < 0.05) were used for ND, DAF24, and DAF36 from 36 h. At 24 to 36 h, DAF decreased the ratio of villus height/crypt depth (VH/CD) in the duodenum but increased VH/CD in the ileum due to changes in CD, whereas at 72 h, DAF decreased VH/CD due to a decrease in VH. The mRNA abundance of PepT1 was upregulated, while Muc2 mRNA was downregulated in DAF chicks. Cells expressing Muc2 mRNA were present along the villi and in the crypts. The ratio of the number of goblet cells found in the upper half to the lower half of the villus was greater in DAF chicks than in ND chicks, suggesting that DAF affected the appearance of new goblet cells. The number of Muc2 mRNA-expressing cells in the crypt, however, was generally not affected by DAF. In conclusion, DAF transiently affected small intestinal morphology, upregulated PepT1 mRNA, downregulated Muc2 mRNA, and changed the distribution of goblet cells in the villi. By 168 h, however, these parameters were not different between ND, DAF24, and DAF36 chicks.

A 'meta-analysis' of effects of post-hatch food and water deprivation on development, performance and welfare of chickens

A 'meta-analysis' was performed to determine effects of post-hatch food and water deprivation (PHFWD) on chicken development, performance and welfare (including health). Two types of meta-analysis were performed on peer-reviewed scientific publications: a quantitative 'meta-analysis' (MA) and a qualitative analysis (QA). Previously reported effects of PHFWD were quantified in the MA, for variables related to performance, mortality and relative yolk sac weight. The QA counted the number of studies reporting (non-)significant effects when five or more records were available in the data set (i.e. relative heart, liver and pancreas weight; plasma T3, T4 and glucose concentrations; relative duodenum, jejunum and ileum weight; duodenum, jejunum and ileum length; and villus height and crypt depth in duodenum, jejunum and ileum). MA results indicated that 24 hours of PHFWD (i.e. ≥12-36 hours) or more resulted in significantly lower body weights compared to early-fed chickens up to six weeks of age. Body weights and food intake were more reduced as durations of PHFWD (24, 48, 72, ≥84 hours) increased. Feed conversion rate increased in chickens up to 21 and 42 days of age after ≥84 hours PHFWD in comparison with chickens fed earlier. Total mortality at day 42 was higher in chickens after 48 hours PHFWD compared to early fed chickens or chickens after 24 hours PHFWD. First week mortality was higher in chickens after ≥84 hours PHFWD than in early fed chickens. The MA for relative yolk sac weight was inconclusive for PHFWD. The QA for plasma T3, T4 and glucose concentrations indicated mainly short-term decreases in T3 and glucose in PHFWD chickens compared to early fed chickens, and no effects of PHFWD on T4 concentrations. Relative weights of liver, pancreas and heart were lower after PHFWD, but only in the first week of life. A retarded development of gut segments (duodenum, jejunum and ileum) was found in the first week of life, measured as shorter, lower relative weight, and lower villus height and crypt depth. It is concluded that 48 hours (≥36-60 hours) PHFWD leads to lower body weights and higher total mortality in chickens up to six weeks of age, the latter suggesting compromised chicken welfare, but effects of PHFWD on organ development and physiological status appear to be mainly short-term.