Changes in hematological, biochemical, and blood gases prameters in response to progressive inclusion of nitrate in the diet of Holstein calves

Background and Aim: Nitrate (NO3-) reduces enteric methane emissions and could be a source of non-protein nitrogen in ruminant feeds. Nonetheless, it has a potential toxic effect that could compromise animal health and production. The purpose of this study was to determine the effects of progressive inclusion of NO3- in the diet on the hematological, biochemical, and blood gases parameters, in turn, the effects on feed intake and live weight gain (LWG) in Holstein calves. Materials and Methods: Eighteen Holstein heifers and steers (nine animals/treatment) were maintained in individual pens for 45 days. Animals were randomly allocated to either a control or nitrate diet (ND) (containing 15 g of NO3-/kg of dry matter [DM]). The biochemical parameters and blood gases were analyzed only in the NO3- group on days: -1, 1, 7, 13, 19, and 25 corresponding to 0, 20, 40, 60, 80, and 100% of the total inclusion of NO3- in the diet, respectively. In addition, DM intake (DMI) and LWG were evaluated among dietary treatments. Results: Feeding the ND did not influence DMI or LWG (p>0.05). Methemoglobin (MetHb) and deoxyhemoglobin increased according to the NO3- concentrations in the diet (p<0.05), while an opposite effect was observed for oxyhemoglobin and carboxyhemoglobin (p<0.05). Hematocrit levels decreased (p<0.05), while albumin, alanine aminotransferase, and gamma-glutamyl transpeptidase concentrations were not modified (p>0.05). However, glucose, urea, aspartate aminotransferase (AST), and retinol concentrations increased (p<0.05) according to the NO3- concentrations in the diet.

Instituto de Patobiología

Fil: Ortiz Chura, Abimael. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Patobiología; Argentina

Fil: Ortiz Chura, Abimael. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Fil: Marcoppido, Gisela Ariana. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Patobiología; Argentina

Fil: Marcoppido, Gisela Ariana. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Fil: Gere, José. Universidad Tecnológica Nacional. División Investigación y Desarrollo de Ingenierías; Argentina

Fil: Gere, José. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Fil: Depetris, Gustavo. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; Argentina

Fil: Stefañuk Bahamonte, Francisco José. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; Argentina

Fil: Trangoni, Marcos David. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Agrobiotecnología y Biología Molecular. Argentina

Fil: Trangoni, Marcos David. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Fil: Cravero, Silvio Lorenzo Pedro. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Agrobiotecnología y Biología Molecular; Argentina

Fil: Cravero, Silvio Lorenzo Pedro. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Fil: Faverin, Claudia. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; Argentina

Fil: Cataldi, Angel Adrian. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Agrobiotecnología y Biología Molecular; Argentina

Fil: Cataldi, Angel Adrian. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Fil: Ceron Cucchi, Maria Esperanza. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Patobiología; Argentina

Fil: Ceron Cucchi, Maria Esperanza. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina