Dietary Supplementation with a Combination of Fibrolytic Enzymes and Probiotics Improves Digestibility, Growth Performance, Blood Metabolites, and Economics of Fattening Lambs

SIMPLE SUMMARY: Sheep meat is one of the most important sources of animal protein throughout the world, specifically in arid and semiarid regions. The meat yield of growing lambs can be maximized by improving the function and health of the digestive system, specifically using sheep diets containing ratios high in fibers. Diets rich in fibrous portions cannot be efficiently hydrolyzed by the endogenous enzymes or by the microbes of the rumen. Therefore, the addition of some feed additives that can improve fiber digestion and/or sustain digestive system eubiosis, such as fibrolytic enzymes, probiotics, and yeast, can be a suitable intervention. Fibrolytic enzymes are gaining importance because they improve the nutrient digestibility and performance of animals without affecting the animals’ health. Probiotics (bacteria and/or yeast) are also important feed additives that can support ruminal microbial activity and enhance gut health and ecology through rumen maturity by favoring microbial establishment. In the present study, dietary supplementation with a combination of fibrolytic enzymes and probiotics (Calfo Care(®)) at 0.5, 1, and 2 kg/ton diet of dry matter increased nutrient digestibility, feed intake and feed conversion, daily weight gain, average total weight gain, and improved most blood parameters of lambs. The addition of 1 kg/ton diet of DM resulted in more economic profit compared with other levels. ABSTRACT: This study was conducted to evaluate the effects of adding different levels of the combination of fibrolytic enzymes and probiotics (a mixture of bacteria and yeast) on the performance of fattening lambs. Thirty-two male Ossimi lambs (weighing 39 ± 0.24 kg) were divided into four groups randomly (eight animals each). The first group (control ration, G1) was fed on a ration of 60% concentrate feed mixture (CFM), 20% Egyptian clover (EC), and 20% wheat straw (WS). The second (G2), third (G3), and fourth (G4) groups were fed a control ration supplemented with Calfo Care(®) at concentrations of 0.5, 1, and 2 kg/ton diet of dry matter (DM). Results showed that the G2 and G3 rations significantly (p ≤ 0.05) increased the DM, organic matter, crude protein, crude fiber, and ether extract digestibility compared with the G1 and G4 rations. Moreover, the G2 and G3 rations increased (p ≤ 0.05) the percentages of total digestible nutrients (TDN), starch values (SV), and digestible crude protein (DCP) compared with the G1 and G4 rations. Both the G2 and G3 rations significantly (p ≤ 0.05) increased the TDN, SV, and DCP as kg/day or g/kg w(0.75) and kg or g/100 kg body weight compared with the G1 and G4 rations. Conversely, the G1 ration significantly decreased the feed conversion of DM, TDN, SV, and DCP compared with the experimental groups. Furthermore, the G2, G3, and G4 rations significantly (p ≤ 0.05) increased the total weight gain by 25.34%, 52.20%, and 3.79%, respectively, compared with the G1 ration. The G2, G3, and G4 rations also (p ≤ 0.05) increased the concentrations of most hematological parameters, including triiodothyronine, total protein, albumin, and glucose, compared with the G1 ration. Finally, the best net profit was recorded with the G3 ration, followed by the G2, G4, and G1 rations.