Effects of the association of proteinate microminerals and amylase on fermentation and ruminal and omasal microbiome, micromineral bioavailability and performance of dairy cows

Abstract

Making the enzymatic activity more efficient in ruminants is still little explored since the association of exogenous enzymes with organic minerals has been widely used in monogastric nutrition. The objective of this study was to evaluate the association of proteinate microminerals with amylolytic enzymes in ruminant supplementation, and their effects on nutrient intake, ruminal fermentation, nutrient digestibility, microbial protein synthesis and productive performance, as well as increasing ruminal feed degradation and nutrient bioavailability. Secondarily, this study will evaluate the bioavailability of proteinate trace minerals as well as their effects on rumen bacterial populations compared to treatments containing inorganic trace minerals. The study hypothesis states that the positive synergistic effect in the association of proteinate minerals with exogenous enzymes in diets of dairy cows on performance, ruminal digestibility, microbial protein flow, and micromineral retained in dairy cows. Eight Holstein dairy cows will be used, four primiparous and four multiparous cannulated in the rumen, with 120 days in lactation, 580 kg of live weight and 35 kg of daily milk production and housed in a tie-stall facility. Days in milk, milk production and BW will be considered to allocate cows, in two contemporary Latin Squares balanced for carry-over effect. Experimental diets will be formulated according to NASEM (2021). The treatments will be arranged in a 2×2 factorial and the experimental diets will be: 1) Inorganic minerals: Diet containing 100% of inorganic minerals (Cobalt Sulfate, Copper, Iron and Manganese, Zinc Oxide, Calcium Iodate and Sodium Selenite ) without the addition of exogenous alpha-amylase (Amaize, Alltech ®); 2) Inorganic minerals with enzymes: Diet containing 100% of inorganic trace minerals (Cobalt Sulfate, Copper, Iron and Manganese, Zinc Oxide, Calcium Iodate and Sodium Selenite) with the addition of exogenous alpha-amylase (Amaize, Alltech® ); 3) Microminerals in proteinate form: Diet containing the majority of micromineral as proteinates [Cobalt, Copper, Manganese and Zinc (BIOPLEX®) and Selenium (SEL-PLEX®)] without the addition of exogenous alpha-amylase (Amaize, Alltech®) 4) Microminerals in proteinate form plus enymes: Diet containing most of the micromineral proteinates [Cobalt, Copper, Manganese and Zinc (BIOPLEX®) Selenium (SEL-PLEX®)] with the addition of exogenous alpha-amylase (Amaize, Alltech®). The roughage:concentrate ratio will be set at 48:52. The four experimental periods will be composed of 21 days each, being 14 days allowed for adaptation to the experimental diets and 7 days of collections. Data will be submitted to analysis of variance using the SAS Mixed procedure (9.4, SAS Institute, Cary, NC, USA) after testing the normality of the residues. The statistical model will include the fixed effects of square, period, type of micromineral (inorganic and organic), enzyme addition, and interaction between these factors, as well as the random effect of animal within square. Ruminal fermentation data will be analyzed as repeated measures in time adding the fixed effects of time and interaction between treatment and time to the previous statistical model