Document Type : Research Paper
Authors
1 PhD. Student, Department of Animal and Poultry Nutrition, Faculty of Animal Science, Gorgan University of Agricultural Science and Natural Resources, Gorgan, Iran.
2 Department of Animal and Poultry Nutrition, Faculty of Animal Science, Gorgan University of Agricultural Science and Natural Resources, Gorgan, Iran
3 Department of Animal and Poultry Nutrition, Faculty of Animal Science, Gorgan University of Agricultural Science and Natural Resources, Gorgan
4 PhD., Department of Animal and Poultry Nutrition, Faculty of Animal Science, Gorgan University of Agricultural Science and Natural Resources, Gorgan, Iran.
Abstract
Introduction: Climate change is a worrying issue that has negative effects on livestock. This global climate situation leads to multiple stresses in livestock, which will affect livestock production and health. Heat stress is the most important stressor that will have detrimental effects on livestock growth and productivity. High temperature and humidity lead to an imbalance between metabolic heat output in the animal's body and its loss to the surrounding environment, resulting in heat stress. One of the solutions to optimize production conditions and livestock health, by improving nutrient metabolism and eliminating or reducing stress conditions, is the use of chromium as a metabolic enhancer. In the condition of stress, the mobilization of glycogen reserves and the production of glucose occur to produce energy to maintain stability in the body. Chromium is one of the scarce essential minerals that plays a role in the metabolism of carbohydrates, lipids, proteins and nucleic acids. Chromium is part of the glucose tolerance factor that increases the affinity of insulin receptors to insulin hormone and increases the sensitivity of receptors to insulin.
Material and Methods: In order to evaluate of the effect of feeding milk enriched of inorganic, organic and chromium nanoparticles supplements on performance, digestibility of nutrients, nutritional behaviors and microbial protein synthesis of Holstein Suckling calves under heat stress conditions, 32 calves with average weight 37± 3 kg in a complete design were randomly selected with 8 replications and 4 treatments. Experimental treatments include milk without chromium supplement (control), milk containing 3 mg of chromium in mineral form per day, milk containing 3 mg of chromium in the form of chromium-methionine per day and milk contained 3 mg of chromium in the form of chromium nanoparticles per day. The duration of the experimental period was 63 days.
Results and Discussion: The results showed that, in calves fed with chromium nanoparticles-enriched milk, significant improvements were observed in final weight, period weight gain, daily weight gain, total dry matter intake, initial dry matter intake, and reduced feed conversion ratio (P≥0.05). Different forms of chromium had a significant effect on dry matter and organic matter digestibility in suckling calves, with the highest dry matter and organic matter digestibility being related to treatments receiving chromium nanoparticles compared to the control treatment (P≥0.05). Chromium supplementation in inorganic, organic, and chromium nanoparticles forms had no effect on the feeding behaviors of calves (P<0.05). However, the standing behavior of calves receiving different forms of chromium increased compared to the control treatment, and the lying behavior decreased (P≥0.05). The intake of different forms of chromium by calves did not cause significant differences in purine derivatives and microbial protein synthesis (P<0.05). However, the amount of urinary uric acid in the control treatment was the highest and the treatment receiving chromium nanoparticles showed the lowest amount (P≥0.05).
Conclusion: In general, the use of chromium, especially in the forms of chromium-methionine and chromium nanoparticles, is recommended in calves affected by heat stress.
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