Effects of Protein Levels and Glutamine Supplementation on Hematological and Immune Parameters, Some Inflammatory Indicators of Afshari fattening Male lambs Under Heat Stress Condition

Heat stress (HS) potentially has several physiological complications that lead to great economic losses in the sheep and goat breeding industry, including reproductive disorders, immune system weakness, inflammation, electrolyte imbalance and reduced feed intake. Glutamine is the most abundant amino acid in the body and this amino acid has different roles such as building proteins, increasing nitrogen balance, stimulating the immune system, anabolic and anti-catabolic effects on muscles, anti-inflammatory and antioxidant. This experiment was conducted to evaluate the effects of glutamine supplementation and protein level (equal to and 10% higher than National Research Council requirement) on blood parameters, inflammatory and immune indices of fattening lambs during heat stress.

In this study, 16 Afshari male lambs with an average weight of 31.5 ± 0.22 kg and an average age of 3 to 4 months were used. Experimental lambs were tested in 4 treatments and 4 repetitions in a completely randomized design for 45 days. Experimental treatments include: 1- basic diet (metabolizable protein equal to requirements), 2- basic diet with glutamine (0.2 grams per kilogram of body weight), 3- diet with 10% more metabolizable protein than reqirements and 4- The diet had 10% higher metabolizable protein with glutamine (0.2 grams per kilogram of body weight). Blood sampling was done from the jugular vein two hours after the morning meal on the 15th, 30th and 45th days of fattening with the help of Venoject tubes containing anticoagulant. Blood parameters including albumin (Alb) and total protein of plasma, alkaline phosphatase and malondialdehyde were measured with relevant kits and with an automatic analyzer. The concentration of cytokines was including interleukin 2, interleukin 6 and interleukin 10 as well as Immunoglobulin G was measured using ELISA kits.

The effects of the treatments on blood Alb on the 15th day of fattening did not show any significant difference. While on days 30 and 45 of fattening, the effects of treatments on blood Alb were significant (P=0.0217 and P=0.0087, respectively). Glutamine increased total plasma protein concentration on days 30 and 45 (P=0.0071 and P=0.0019, respectively). Also, increasing the protein level in the diet of fattening lambs on days 30 and 45 increased TP of plasma (P=0.0139 and P=0.0386, respectively). On the 45th day of fattening, addition of glutamine increased blood ALP enzyme (P=0.0123). Also, taking glutamine supplement on the 30th and 45th days of fattening decreased MDA (P=0.0012 and P=0.0029, respectively). There was no significant difference in the number of red blood cells, hemoglobin level, hematocrit, mean concentration of hemoglobin in cells and mean cell volume between treatments on the 15th and 30th days of fattening. While on day 45, glutamine decreased the number of red blood cells and hematocrit percentage (P=0.0036 and P=0.0081, respectively). The number of white blood cells increased on the 30th and 45th days of fattening with the addition of glutamine (P=0.0004 and P=0.0012, respectively). The effect of treatments on blood IgG, IL-2 and IL-10 on the 15th day of fattening was not significant, while the treatments on the 30th and 45th day of fattening increased the values of IgG (P=0.0287 and P<0.0001, respectively). In addition, IL-2 increased on days 30 and 45 under the influence of treatments (P<0.0001 and P<0.0001, respectively). On the 30th and 45th days of fattening, addition of glutamine increased the levels of IL-10 (P=0.0194 and P=0.0007, respectively). The concentration of IL-6 on the 45th day of fattening decreased with the addition of glutamine and the addition of metabolizable protein level (P=0.0004 and P=0.0233, respectively).

In the conditions of this experiment, the basic diet with glutamine showed better results than other diets.