The influence of different dietary protein sources and two types of pro-nutrients e.g. enzyme mixture containing phytase and probiotics on growth performance, carcass characteristics, meat quality and plasma biochemical constituents of broiler chicks was studied herein as means of improving the utilization of diets containing different plant protein sources and decreasing feed cost. A complete randomized straight run experimental design including 10 dietary treatments was conducted. A basal control corn-soybean meal diet containing 22 and 20% CP in the starting and growing-finishing periods, respectively was formulated. Sunflower meal (SFM) and rocket (Eruca sativa) meal (RM) individually or as a mixture of (1:1; Wt::Wt ) replaced 25% of soybean meal protein. Thus, there were four main experimental diets. Moreover, the diets containing SFM and/or RM was either supplemented or not with enzyme mixture containing phytase (Natuzyme) or probiotics (Nutri-Bio Plus). Thus, there were 10 experimental treatments, Each diet was fed to 24 one d-old unsexed broiler chicks divided equally among four replicates of 6 chicks each housed in a battery (30×35×40 cm). At the end of the experiment (49 d of age), 3 chicks of each treatment were slaughtered to determine carcass characteristics and meat quality traits. Furthermore, four blood samples per treatment were collected to determine some biochemical constituents. Also, a digestibility trail and an economic efficiency study were carried out.
Although, substituting 25% of soybean meal protein by SMF and/or RM had no adverse effect on growth or feed conversion ratio (FCR) it improved protein conversion ratio (PCR) and economic efficiency of broiler chicks. Furthermore, Natuzyme and probiotics supplementation significantly improved growth, FCR, PCR and the economic efficiency, with the effect of probiotics was more efficient. Feed intake was significantly decreased due to inclusion of SFM and/or RM and further decreased by enzymes and probiotic supplementation, however, the effect of probiotics was stronger than enzymes. Enzyme supplementation improved significantly digestibility of dry matter of diet containing a mixture of SFM and RM. Sunflower meal and/or RM had no effect on dressing percentage, front and hind parts, meat quality and plasma total protein, globulin and albumin/globulin ratio, total lipids, cholesterol, inorganic phosphorous (iP), Ca and AST and ALT enzymes.
In conclusion, SFM and/or RM could be included in broiler diets to replace 25% of soybean meal protein without adverse effects on growth performance and economic efficiency. Furthermore, enzyme mixture and probiotics supplementation resulted in improved growth performance and economic efficiency. Whereas, probiotic supplemented-diet containing a mixture of SFM and RM resulted in the best productive performance and economic efficiency.