Blend of secondary metabolites from mesquite to improve nutrient digestibility, microbial protein, efficient use of nitrogen, ruminal parameters, and blood metabolites in sheep.

Although chemical additives are able to improve the efficiency of ruminal fermentation, they can leave residues in the meat. However, a blend of secondary metabolites can improve ruminal fermentation without harming the population welfare. Five levels (0.0, 1.5, 3.0, 4.5, and 6.0 g/day) of a blend of secondary metabolites from mesquite extract in sheep feed to promote increases in the nutritional value, ruminal parameters, nitrogen (N) use efficiency, microbial protein (MP) synthesis, and blood metabolites. Ten intact male Santa Inês sheep with average body weight of 55 ± 9.81 kg were used in a 5 × 5 Latin square design, replicated twice. There was a quadratic response of the digestibility of dry matter (DM), organic matter (OM), crude protein (CP), and total digestible nutrients (TDN). Microbial protein concentrations, MP synthesis efficiency, propionic acid levels, and acetic/propionic acid ratio also showed a quadratic response. The blend promoted a quadratic effect on plasma glucose and lactate levels. On the other hand, it decreased the concentrations of ammoniacal nitrogen, plasma urea, and plasma cholesterol. It is recommended to supply a blend of secondary metabolites at 3.43 g/day.

Dwarf versus tall elephant grass in sheep feed: which one is the most recommended for cut-and-carry?

Tall- and dwarf-sized elephant grass cultivars have been developed for cut-and-carry system. Dwarf clones have better digestibility; on the other hand, tall-sized cultivars are more productive. The aim was to verify which grass would be most recommended for cut-and-carry: tall-sized (Elephant B and IRI-381) or dwarf (Taiwan A-146 2.37 and Mott) elephant grass cultivars to feed 24 male sheep, aged between 4 and 5 months, uncastrated, weighing approximately 24.08 ± 1.76 kg body weight which were sampled on intake, digestibility, performance, ingestive behavior, nitrogen balance, microbial protein synthesis, metabolic parameters, and ruminal degradability. This research was divided into two experiments: experiment 1 lasted 38 days, seven for adaptation and 31 for data collection. Elephant grass cultivars were supplied with a mineral mixture. Data collected were intake, digestibility, ingestive behavior, metabolic parameters, microbial protein synthesis, and performance submitted to a completely randomized design. For experiment 2, three rumen fistulae animals were sampled, lasting 20 days. In this case, a randomized block in split-plot design was applied. Both designs were with P < 0.05 and analyzed through SAS statistical software. Mott and Taiwan A-146 2.37 cultivars provided greater intake, digestibility, weight gain, feeding time, nitrogen retention, production and efficiency of microbial protein synthesis, dry matter (DM) and neutral detergent fiber (NDF) degradability, and DM, crude protein, and NDF, but shorter rumination time rather than Elephant B and IRI-381. There was also a significant difference for glucose, triglycerides, plasma urea, total serum protein, urinary urea (mg/L), and urea excretion in urine (mg/day). Dwarf elephant grass cultivars as Mott and Taiwan A-146 2.37 have greater nutritional value than tall-sized Elephant B and IRI-381. Dwarf elephant grass is recommended for cut-and-carry system.