effect of probiotic supplementation on the growth performance, blood biochemistry and immune response of reciprocal F1 crossbred (Rhode Island Red×Fayoumi) cockerels

A study was conducted to evaluate three different probiotic levels, using drinking water supplemented with 0 (control), 1, 2 or 3 ml/L of Protexin (probiotic). In a 2×4 factorial design, 360 of each reciprocal crossbred (Rhode Island Red [RIR]×Fayoumi [FY]) cockerels (six weeks old) were randomly assigned to four dietary treatments. Each diet was offered to three pens of 30 RIR×FY cockerels each or three pens of 30 FY×RIR cockerels each. At 12 weeks of age, body weight (BW) and feed conversion were determined. At the end of 42 d of experiment, 12 birds per treatment were slaughtered to evaluate carcass characteristics, abdominal fat contents and the internal organs. Blood haemato-biochemical parameters were also determined. Haemagglutination inhibtion antibody titres against Newcastle disease virus and lymphoid organs weight/body weight ratio were also determined. The BW and better feed conversion of birds given 3 ml/L of probiotic in drinking water was significantly greater than birds given water without probiotic. The cockerels of FY male×RIR female had higher growth rate than the cockerels of RIR male×FY female in all groups. There was no mortality recorded at higher levels of probiotic in both strains. Differences in carcass characteristics, organs weight, meat composition, haematological values and high-density lipoprotein and low-density lipoprotein concentrations among all the groups were nonsignificant. However, abdominal fat and cholesterol contents were reduced significantly in supplemented groups. Feeding levels of 2–3 ml/L of probiotic, did positively affect the immune system within the parameters measured. It may be concluded that performance, blood chemistry and immunity against disease in cockerels could be maintained when supplementing high level of probiotic incorporated in crossbred cockerel's drinking water.