The effect of single-cell diets and probiotics on the weight of internal organs, some reproductive indices, and intestinal traits in Leghorn laying hens

Abstract

Introduction: An experiment to investigate single-cell protein replacement with soybean meal and adding probiotics to the diet, of the relative weight of internal organs (liver, pancreas, bile, spleen, and heart), and reproductive organs (Oviduct, Ovary), the number of ovarian follicles, and the pH of intestinal contents and feces were performed in laying hens aged 42 to 52 weeks. Materials & Methods: One hundred and eighty, Leghorn Hy-line W36 white layer hens, were used in the form of a 3×3 factorial test and based on a completely randomized design with 9 treatments, 4 repetitions, and 5 birds per replication. The factors studied consisted of three levels of soybean meal replacement with single-cell protein (zero, 30, and 60 %) and three probiotic levels (zero, 50, and 100 mg/kg). The experimental period lasted 70 days, and throughout the test period, water was at libitum, and feed was provided to the birds as recommended by the catalog. At the end of the experiment, two birds from each replicate were slaughtered and the relative weight of the liver, pancreas and bile, spleen and heart, oviduct and ovary, as well as the pH of the intestine and feces and the separate count of the ovarian follicles were examined. Results: The relative weight of organs and internal reproduction were not affected by different factors in a single-cell diet. However, supplementing the diet with probiotics increased the weight of the gallbladder (p<0.05), spleen (p<0.04), and the marginal increase of the pancreas (p=0.08) and the marginal decrease of the liver (p=0.07). The interaction effects of single-cell protein and probiotics on the weight of reproductive organs were not significant. The addition of single-cell protein and probiotics to the diet had no effect on the weight of reproductive organs and the number of ovarian follicles in laying hens (P<0.05). Substituting 30% soybean meal with single-cell production and adding probiotics to the diet decreased the pH of ileum contents (P<0.01). Conclusion: The results of the present study show that the replacement of soybean meal with single-cell protein did not show an adverse effect on the traits studied. Also, the addition of 100 mg of probiotics improves the relative weight of some internal organs (spleen and gall bladder) and reduces the pH of the ileum contents of the intestine.