Feed intake, nutrient digestibility, nitrogen utilization, and ruminal fermentation activities in sheep fed Atriplex halimus ensiled with three developed enzyme cocktails

Abstract

The effects of feeding Atriplex halimus treated with three developed enzyme cocktails to Barki sheep on feed intake, nutrient digestibility, N utilization, and ruminal fermentation were assessed. A. halimus was ensiled with two developed enzyme cocktails of ZAD1® (Z1) and/or ZAD2® (Z2) as liquid enzyme preparations (2 l/t) with 5% molasses and ensiled for 30 days. Three Barki rams (45 ± 3.2 kg) were used per treatment in five consecutive digestibility trials, while three ewes fitted with a permanent rumen fistula were used as source of inoculum for in vitro rumen fermentation trials. Barley grain (300 g/animal/day) was fed as energy supplement during the experimental trial for all diets. Five diets were composed as follows: A. halimus (leaves and stems) (D1); untreated A. halimus plus 4 g/animal/day ZADO® (Z) (enzyme preparation in powder form) (D2); A. halimus ensiled with Z1 and barley plus 4 g/animal/day Z (D3); A. halimus ensiled with Z2 and barley (D3) plus 4 g/animal/day Z (D4); A. halimus ensiled with a combination of Z1 and Z2 (1 :1) and barley plus 4 g/head/day Z (D5). For all trials, ad libitum A. halimus was offered twice a day at 9:00 and 16:00 h while barley grain was given once a day at 10:00 h. Both D1 and D2 diets increased (P <0.001) dry matter intake of A. halimus and total dry matter intake. Addition of 4 g/day of Z to Z1 and/or Z2 ensiled diets improved (P < 0.0001) organic matter, crude protein, crude fibre, and neutral detergent fibre digestibilities. Diets D1 and D2 increased (P < 0.001) N intake, whereas the direct addition of Z to D3, D4, and D5 decreased (P < 0.001) N balance and N balance/N absorption ratio. Sheep fed on Z in addition to Z2 ensiled A. halimus showed higher improvements for total volatile fatty acids (P < 0.001), ammonia N (P = 0.007), and microbial protein production (P = 0.003). It can be concluded that feeding sheep on A. halimus ensiled with Z1 and Z2 with direct feeding of Z enzyme preparation improved intake, digestibility, nitrogen balance and utilization, as well as rumen fermentation.