Effects of replacing soybean meal with cottonseed meal on growth performance, carcass trait, intestinal development and intestinal microbiota of broiler chickens

Abstract

<p>This experiment was conducted to evaluate the effects of replacing soybean meal (<b>SBM</b>) with cottonseed meal (<b>CSM</b>) on growth performance, carcass trait, intestinal development and intestinal microbiota of broilers. A total of 792 one-day-old male Ross 308 broiler chickens were randomly allotted to three treatment groups, with 8 replicates per group and 33 birds per replicate. The control birds were administered a diet consisting primarily of corn and soybean meal. The two treatment groups were fed a similar diet with the soybean meal partially substituted by 5 % (5 % CSM group) or 10 % cottonseed meal (10 % CSM group). The experiment lasted 37 days.</p> <p>Results showed that in the starter phase, the 10 % CSM group had a higher feed conversion ratio (<b>FCR</b>) and a lower average daily feed intake (<b>ADFI</b>) compared to the control group and the 5 % CSM group (<i>P</i> < 0.05). Notably, the 10 % CSM group had the lowest body weight (<b>BW</b>) at 15 days of age (<i>P</i> < 0.05) among all treat ments. In the grower phase, there were no significant differences in BW, average daily gain (<b>ADG</b>), and FCR of broilers among all groups (<i>P</i> > 0.05). In the finisher phase, both the 5 % and 10 % CSM groups significantly decreased ADG, and the 10 % CSM group significantly decreased ADFI (<i>P</i> < 0.05). There were no significant differences in final body weight, ADG and ADFI among treatments from 1 to 37 days (<i>P</i> > 0.05). No significant effect of CSM was observed on the slaughter performance of broiler chickens. Compared with the basal diet, 5 % CSM significantly decreased the weight/length index of broiler ileum and the relative weight of duodenum and jejunum at both levels (<i>P</i> < 0.05). Moreover, 5 % and 10 % CSM significantly decreased breast meat pH in 24 h (<i>P</i> < 0.05). Cottonseed meal had no significant effect on the alpha diversity, beta diversity, and taxonomic composition at the phylum and genus levels of the ileal microbiota in broilers (<i>P</i> > 0.05). However, Spearman correlation analysis revealed a strong correlation (<i>P</i> < 0.05) between several bacterial phyla (genera) and the growth performance as well as slaughter performance of broilers.</p> <p>In conclusion, the effect of replacing SBM with CSM in broiler diet on growth performance of broilers varied at different ages. Thus, incorporating 10 % CSM resulted in decreased growth performance during the starter phase, while both 5 % and 10 % CSM levels had similar negative effects during the grower phase. In the finisher stage, the use of 5 % CSM influenced gut weight and meat pH but had no influence on slaughter performance, intestinal health and ileal flora structure of broilers. </p>