Response of Broiler Chicks to Various Levels of Dietary Probiotic, Prebiotic and Synbiotic as Natural Growth Promoters

Abstract

Three experiments were conducted to evaluate the response of broiler chicks to diet containing various levels of dietary commercial natural products which are Bacterial Probiotic Biogen.S (BPB), Prebiotic Y-MOS (PYM) and Synbiotic Biogen.S + Y-MOS 1:1 (SBYM) as natural growth promoters. Experiment parameters covered growth performance, carcass characteristics, serum attributes and economic appraisal of broilers. The experimental design used was complete randomize design (CRD). A total of 288, five days old, 170g initial weight, unsexed Cobb-500 strain broiler chicks were used. The chicks were divided into 3 experimental groups of 96 birds in each experiment, and randomly assigned to 4 treatment diets with three replicates, each of eight chicks (3x4x3x8). The first group A fed on basal diet without feed additives as control diet, the other groups B, C, and D were fed on basal diet supplemented with one of tested products, in each experiment at graded levels of (0.5, 1.0 and 1.5g/kg) respectively. The basal diet was formulated to meet the nutrients requirements of broilers according to (NRC, 1994). Experimental diets were fed for five weeks. The results recorded no mortalities throughout the experimental period. The application of dietary BPB, PYM and SBYM at all inclusion levels improved significantly (p≤0.05) the broilers performance compared to control without any effect on feed intake of broilers. The results also, reveal that, the addition of dietary BPB, PYM and SBYM in broiler diets significantly (p≤0.05) affect carcass dressing percentages. The results showed no significant differences (p≥0.05) among all treatment groups in giblets percentages (gizzard, liver and heart) and non-carcass components except intestine length, the inclusion levels 1.0 and 1.5g/kg of dietary PYM and SBYM had recorded significantly (p≤0.05) the longest means values of an intestine as compared to the inclusion level 0.5g/kg and control. Also, the addition of dietary BPB, PYM and SBYM in broiler diets recorded no significant differences (p≥0.05) in percentages of commercial cuts and their meat (breast, thigh and drumstick) and the subjective and objective meat quality attributes, the same trend for serum metabolites (total protein, albumin, creatinine, uric acid, urea, cholesterol, HDL, LDL, triglyceride and glucose), serum enzymes (AST and ALP) and serum minerals (Ca and P) of broilers, except the dietary SBYM at all inclusion levels recorded significantly higher means values of serum minerals (Ca and P) compared to control. The results of interaction between dietary Probiotic, Prebiotic, Synbiotic and their levels recorded significant improvement in body weight, body weight gain and FCR with increasing inclusion level compared to control diet, whereas, Synbiotic treatment obtained the best performance followed by Prebiotic, and then Probiotic, and the level 1.5g/kg recorded the best level followed by 1.0g/kg, and then 0.5g/kg. The results of economical evaluation of experimental diets showed that, the addition of dietary BPB, PYM and SBYM at all inclusion levels are economically profitable compared to control, although the level 1.5g/kg of all tested products was more profitable (1.54, 1.67 and 1.73 respectively). The results of comparative between treatments Probiotic, Prebiotic and Synbiotic in profitability ratio showed that, Synbiotic treatment was more profitable followed by Prebiotic, and then Probiotic. According to the results of these studies, dietary Probiotic, Prebiotic and Synbiotic could be considered as potential natural growth promoters without any adverse effect, and can be used as replacement for antibiotics in broiler diets.