Influence of partial replacement of alfalfa with two Salicornia forages on digestion, rumen variables, blood biochemistry metabolites and antioxidant capacity in sheep

Abstract

In a completely randomized design, 24 Shall rams (average initial body weight [BW]: 43 ± 1.4 kg, aged 1.5 years) were used to evaluate the effects of partial replacement of alfalfa (Medicago sativa) hay with 2 species of Salicornia forage (i.e. bigelovii and persica) on in vivo total tract apparent digestibility, estimated microbial N synthesis (EMNS), rumen fluid parameters, blood metabolites, total antioxidant capacity (TAC) and production of methane in vitro. The three diets offered to sheep (8 per diet) prepared on a dry matter basis were 1- alfalfa hay (990 g/kg DM) + 10 g/kg DM vitamin-mineral supplement (control; AD), 2- alfalfa hay + Salicornia bigelovii (SBF) + vitamin-mineral supplement at a ratio of 690:300:10 (SBD), and 3- alfalfa hay + Salicornia persica (SPF) + vitamin-mineral supplement at a ratio of 690:300:10 (SPD). Salicornia diets did not affect DM, organic matter, crude protein or neutral detergent fiber digestibility. There was no dietary effect on in vivo ruminal pH, volatile fatty acids, or in vitro methane production. Salicornia diets increased rumen concentration of ammonia-N, total numbers of protozoa, and the population of Entodiniinae, whereas the cellulolytic bacteria population and EMNS decreased. Feeding SBD and SPD had no effect on the concentration of plasma albumin, cholesterol, glucose, total protein, triglyceride, and the albumin-globulin ratio but urea-N and TAC increased. Overall, replacing part of the alfalfa hay ration with SBF or SPF improved TAC in sheep with no negative effects on nutrient digestibility or in vitro methane production. This trial showed that Salicornia could be used as a partial substitute for conventional forage in the diet of sheep.