The effect of different levels of probiotic yeast supplement (Saccharomyces servicii) in the diet on growth performance, carcass traits, and some blood and rumen parameters in Zell*Atabai cross-breed fattening lambs

This study was conducted to evaluate the effect of different levels of probiotic yeast supplement (Saccharomyces servicii) in the diet on growth performance, carcass traits, and some blood and rumen parameters in Zell cross-breed fattening lambs. For this purpose, a total of 24 crossbred of Zell-Atabai lambs with a mean weight of 26±2 kg and a mean age of 5.5 months were used in a completely randomized design with 4 treatments and 6 replications for 90 days. The results of growth performance showed that the treatment with 8 grams of probiotic supplement significantly had the highest final fattening weight, daily weight gain and the lowest feed conversion ratio (P<0.05). In apparent digestibility of nutrients, treatment with 8 grams of probiotic supplement had the highest digestibility of crude protein and NDF (P<0.05). In the results of blood parameters, there was a significant difference in the concentration of glucose, cholesterol and HDL between experimental treatments (P<0.05). The results of carcass traits showed that in live weight, thigh percentage and shoulder percentage, treatment with 8 grams of probiotic supplement significantly had the highest values (P<0.05). The highest value of pH, VFA, acetic acid, propionic acid, total population of bacteria and ruminal fluid protozoa was observed respectively in the treatment of 8 grams of probiotic supplement (P<0.05). The general result of the research showed that the consumption of 8 grams of yeast probiotic supplement improved growth performance, valuable carcass parts, apparent digestibility and morphological characteristics of rumen villi in fattening lambs.