Inclusion of Berberis vulgaris leaf in the diet of fattening lambs: effects on performance, nutrient intake, rumen fermentation, and carcass traits

This study was aimed to first, determine the nutritional value of Berberis vulgaris leaf (BVL), using in vitro gas production technique and second, determine the effect of replacing alfalfa hay (AH) with BVL in lamb diets on nutrient intake, performance, and carcass traits. In vitro rumen gas kinetics and fermentation profile were assessed using three fistulated lambs and 96 h incubation of samples. For the in vivo trial, 21 Baluchi male lambs of 5-6 mo of age and 30.6 +/- 1.28 kg body weight (BW) were randomly assigned to three treatment diets containing BVL at 0% (CTRL), 7.5% (BVL7.5), and 15% (BVL15) of the total dry matter (DM) inclusion. The study lasted 84 d, which included 14 d for adaption and 70 d for sample collection. In vitro results showed that BVL had lower gas yield (GY24, P <= 0.05) than AH. In vivo trial revealed that DM intake increased with BVL15 followed by BVL7.5 (P <= 0.05). Digestibility of DM, organic matter, NDF, and acid detergent lignin decreased (P <= 0.05) with BVL15. Total weight gain, average daily gain, hot carcass weight, and cold carcass weight were decreased (P <= 0.05) with BVL15, however, no differences were observed between the BVL7.5 and CTRL groups. Feed cost per kilogram BW gain decrease (P <= 0.05) by increasing the inclusion levels of BVL. In conclusion, BVL (up to 7.5% DM of diet) have positive consequences on performance, nutrient intake, rumen fermentation without deleterious effects on fattening performance. Replacement of alfalfa hay with Berberis vulgaris leaf (BVL) changed the fermentation parameters in vitro due to its rich bioactive compounds including alkaloids, flavonoids, and tannin. Moreover, the dietary inclusion of BVL (up to 7.5% dry matter of diet) for fattening lambs improved nutrients digestibility and reduced production costs without severe deleterious effects on performance. Barberry (Berberis vulgaris) leaf (BVL) is an agricultural by-product rich in plant secondary compounds such as alkaloids, flavonoids, anthocyanins, and tannin. The present study was aimed to first, evaluate in vitro nutritional value of BVL and second, explore the effects of BVL inclusion in finishing lambs diet (at levels of 0%, 7.5%, and 15% dry matter [DM] of diet), in partial replacement of alfalfa hay, on performance, carcass characteristics, and ruminal fermentation. BVL had less crude protein, ash, and natural detergent fiber than alfalfa hay, but more phenolic compounds and total tannin. The dietary inclusion of BVL at 7.5% and 15% DM of diet enhanced dry matter intake in fattening lambs and affected apparent digestibility. The relationship between nutrient intake and digestibility (DM, organic matter, neutral detergent fiber, and acid detergent fiber) was optimal with 7.5% BVL inclusion. The highest levels of dietary BVL were associated with lower weight gain; however, the production costs were reduced by BVL inclusion, and return per kilogram body weight gain was improved. However, additional trials are needed to refine the potential effects BVL on ruminal fermentation, methane emission and quality of products.