Reproductive and Productive Performance and Blood Metabolites of Barki Ewes Fed on Different Sources of Dietary Protein under South Sinai Conditions, Egypt

Abstract

This study aimed to investigate the effects of replacing soybean meal (SBM) with either undecorticated cottonseed meal (CSM) or fresh Azolla pinnata (AZL) on the productive performance, reproductive efficiency and blood metabolic status of Barki ewes. Thirty-six pregnant Barki ewes were randomly assigned to three equal treatment groups (n=12). The 1st group served as control group (G1) and fed a diet containing 18.0% SBM. The 2nd group (G2) was fed a diet where SBM was replaced by 18% CSM, and the 3rd group (G3) received a diet with 18% fresh AZL instead of SBM. Diets were formulated to be iso-caloric and iso-nitrogenous. The results indicated that, while conception and lambing rates were not significantly different, ewes in the G3 (AZL) group achieved a 100% weaning rate with zero lamb mortality, which was notably better than the G1 (8.33% mortality) and G2 (9.09% mortality) groups. Ewes in G3 demonstrated superior body weight gain during gestation and after lambing, as well as heavier lamb birth weights and weaning weights, and higher daily weight gains in lambs (P<0.01). Milk yield was comparable between G1 and G3, and significantly higher than G2 (P<0.01). Milk composition, including fat, protein, lactose, ash, solids non-fat (SNF), and total solids (TS), showed variations across groups, with G3 generally supporting favorable milk quality. Conversely, the G2 (CSM) group exhibited signs of metabolic stress,
including significantly elevated liver enzymes (AST and ALT) and kidney functions parameters (Urea and Creatinine). Thyroid hormones (T3 and T4) and protein profiles (TP, Alb, Glu, A/G ratio) also varied, with G3 group generally demonstrating more optimal values than other groups. In conclusion, Azolla pinnata meal proved to be a promising alternative protein source for Barki ewes, positively
influencing reproductive and productive performance, lamb growth, and metabolic health, suggesting its potential for sustainable sheep farming.