The present study was conducted to investigate the effect of dietary supplementation of probiotic and drinking water (DW) supplemented with different levels of vinegar on performance, meat yields, immune responses, and small intestine histology of broiler chickens. Three hundred thirty day-old Ross 308 male broiler chicks assigned to six treatments in a completely randomised design experiment with a factorial arrangement (2 Â 3) and five replicates of 11 chicks each. The treatments included two levels of dietary probiotic supplementation (0 and 1 Â 10 10 CFU lactic acid/kg of diet) and three levels (0%, 1%, and 2%) of DW supplemented with vinegar (5% acetic acid concentration). The study lasted from 1 to 42 d. Growth performance, meat yields and lymphoid organs relative weight, humoral and cellular immune responses, and small intestine histomorphometry were measured. The average daily feed intake (ADFI) and feed conversion ratio (FCR) during 1-10 days of age significantly decreased in the birds that fed supplemented diet with probiotic and drunk supplemented water with vinegar than the birds fed and drunk free of any additive. Experimental treatments did not have a significant effect on performance during other growth periods, carcase yields, and lymphoid organs relative weight. DW supplemented with vinegar significantly increased villus height (VH), crypt depth (CD) and decreased small intestine muscular thickness (MT) and abdominal fat. Dietary supplementation of probiotic significantly improved immune response to sheep red blood cell (SRBC) inoculation. In conclusion, this study confirms beneficial effects of probiotic and vinegar on 1-10 d performance, immune and intestine health of broiler chickens.

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This experiment was conducted to evaluate the effects of dietary digestible sulphur amino acids (DSAAs) level on growth performance, blood metabolites, and liver functional enzymes of broilers during 1-11 days of age. Additionally, DSAAs requirement was determined from dose nutrient response data. A total of 432 1-day-old male Ross 308 broilers were allocated to six dietary treatments, graded levels of supplementary DL-Met (þ0.8 g/kg per level) while Cys was equal across groups, led to levels of 0.62, 0.70, 0.78, 0.86, 0.94 and 10.2% DSAAs, with six replicates and 12 birds each. Increasing levels of dietary DSAAs enhanced live body weight (LBW), weight gain (WG), feed efficiency (FE), European Production Efficiency Factor (EPEF), and relative breast weight (RBW), although there was no effect on feed intake. At the end of the starter period, a linear increase in blood serum total protein and albumin concentration was concomitant with decreasing in triglyceride, whole cholesterol, high-density lipoprotein, low-density lipoprotein, creatinine, and aspartate aminotransferase concentration when dietary DSAAs level was increased. The DSAAs requirements estimated by linear broken-line (LBL) fit model to optimise LBW, WG, FE, EPEF and RBW were 0.80, 0.81, 0.93, 0.95 and 0.93%, although the estimated values by the quadratic broken line fit model were 14.32, 19.93, 16.85, 23.68 and 5.79% higher than those, respectively. It is concluded, a minimum of 0.95% DSAAs concentration in broiler starter diet is suggested to optimise growth performance. Estimation of DSAAs requirement depended on what production parameter and regression model are taken considered for optimisation. HIGHLIGHTS A minimum of 0.95% digestible sulphur amino acids level is suggested in the broiler starter diet to optimise growth performance.

This study was done to evaluate the effects of different dietary digestible lysine (dig Lys) levels on growth performance, blood metabolites, carcass and breast yield, and breast meat quality of broilers 23–38 days of age. Three hundred 23‐day‐old Cobb‐500 male broiler chickens were allocated to a completely randomized design with five treatments (finisher diet containing 0.88%, 0.94%, 1.00%, 1.06% and 1.12% dig Lys) and six replicates of 10 birds each. Feed intake (FI) was not affected by different dietary dig Lys levels. Weight gain (WG) linearly increased and feed conversion ratio (FCR) linearly decreased with an increasing dietary dig Lys levels. With increasing dietary dig Lys levels, carcass and breast yield and breast meat hue angle (h*) linearly increased, but abdominal fat decreased quadratically, whereas breast meat lightness (L*) and ether extract composition linearly decreased. Dietary dig Lys levels did not show any significant effect on serum metabolites, breast meat cooking loss and water holding capacity. Based on the linear broken‐line regression models, the weight gain, feed conversion ratio and breast yield were optimized when dietary dig Lys levels were 0.95%, 1.01% and 1.02% respectively. It is concluded that Lys requirements vary according to what productive parameter is taken for optimization. A minimum of 1.02% dig Lys concentration in the finisher diet is suggested to optimize breast yield, feed efficiency and performance in broiler chickens.

Effect of diet nutrients density on performance and egg quality of laying hens during the postpeak production phase of the first laying cycle under subtropical climate,