The effect of probiotic (Lactobacillus sporogenes) feeding on egg production and quality, yolk cholesterol and humoral immune response of White Leghorn (WL) layer breeders was studied. WL layer breeders (24 weeks) were randomly distributed into three groups of 28 each and were housed in individual California type cages. Considering one bird (individual feeding) as a replicate, 28 such replicates were randomly allotted to one of the three dietary treatments: basal (control) or basal with probiotic supplementation at a rate of 100 or 150 mg kg −1 feed. The probiotic used in the study was a commercial preparation containing L. sporogenes with 6000 million spores g −1 of the product. Dietary supplementation of L. sporogenes at 100 mg (6 × 10 8 spore) kg −1 diet significantly increased egg production and feed efficiency. However, body weight gain, feed intake, egg weight, specific gravity and Haugh unit was not influenced by probiotic feeding. The eggshell breaking strength, shell weight and shell thickness increased significantly by feeding 100 mg probiotic kg −1 diet. The serum concentration of calcium and protein increased, and that of cholesterol decreased by L. sporogenes supplementation. The yolk cholesterol followed the same trend of serum cholesterol. Feeding of L. sporogenes significantly enhanced antibody production. No difference in antibody production could, however, noticed between the levels (100 or 150 mg) of probiotic. It is concluded that feeding of L. sporogenes at 100 mg (6 × 10 8 spore) kg −1 diet significantly enhanced the egg production, shell quality and humoral immune response of WL layer breeders during 25-40 weeks of age.

BACKGROUND The present study evaluated the potential of increasing dietary levels of the most limiting amino acids such as total sulfur amino acids (TSAA) with respect to mitigating the adverse effects of the inclusion of guar meal (GM) in the diet of WL layers on egg production, feed efficiency and egg weight. In total, 4928 WL (Lohmann L) hens (32 week of age) were randomly allotted to eight treatments with seven replicates of 88 birds. The dietary treatments were a set of four maize–soybean meal based diets containing four graded concentrations of TSAA (5.85, 6.18, 6.51 and 6.84 g kg−1) and another set of four diets containing 100 g kg−1 guar meal (GM) with similar concentrations of TSAA. RESULTS The inclusion of 100 g kg−1 GM in the diet caused a 20%, 23%, 35.5% and 6.7% reduction in egg production, daily egg mass, feed efficiency and egg weight, respectively, when the diet contained 5.85 g kg−1 TSAA. Increasing TSAA levels in GM groups reduced the adverse effects on egg production and feed efficiency 50%, with no effect on egg weight. The TSAA requirement of WL birds fed 10% GM was estimated as 6.28–7.39 g kg−1 diet at different ages. CONCLUSION Increasing dietary TSAA to 7.39, 6.28, 6.53 and 6.37 g kg−1 or dTSAA (digestible TSAA) to 6.53, 5.32, 5.80 and 5.63 g kg−1 during 33–36, 37–40, 41–44 and 45–48 weeks of age, respectively, may be an effective and practical strategy for reducing the adverse effects of inclusion of 100 g kg−1 GM in the diet of WL layers. © 2018 Society of Chemical Industry