~ 533 ~ International Journal of Chemical Studies 2019; 7(4): 533-541 P-ISSN: 2349–8528 E-ISSN: 2321–4902 IJCS 2019; 7(4): 533-541 © 2019 IJCS Received: 16-05-2019 Accepted: 18-06-2019 Preeti Lakhani Animal Physiology Division, ICA R- National Dairy Research Institute, Karnal, Haryana, India Parveen Kumar Animal Physiology Division, ICA R- National Dairy Research Institute, Karnal, Haryana, India Neeti Lakhani Animal Nutrition Division, ICA R- National Dairy Research Institute, Karnal, Haryana, India Aamrapali Bhimte Animal Physiology Division, ICA R- National Dairy Research Institute, Karnal, Haryana, India Correspondence Preeti Lakhani Animal Physiology Division, ICA R- National Dairy Research Institute, Karnal, Haryana, India Effect of dietary betaine supplementation on growth performance, immunity and oxidative stress in Karan fries heifers during heat stress Preeti Lakhani, Parveen Kumar, Neeti Lakhani and Aamrapali Bhimte Abstract Thermal stress leads to increase in blood supply to the periphery and a compensatory reduction in the blood supply to the gut leading to increase production of endotoxins in the body causing injury to the organ and increase in acute phase protein responses in the body. Therefore, a need arises of an antioxidant that protects the gut integrity. Recently betaine, a trimethyl form of glycine has been found to ameliorate heat stress. The experiment was divided into two parts. Experiment-I (thermoneutral conditions) and Experiment–II (summer season : hot-dry and hot-humid season) were carried out on eighteen female Karan Fries heifers were taken and randomly divided into 3 groups (n = 6) such as control, Treatment I (Betaine supplemented @ 25g/d/animal), Treatment II (Betaine supplemented @ 50g/d/animal) when the average maximum and minimum temperatures were (23.5°C and 9.9°C) and (35.3°C and 22.4°C), respectively. Betaine supplementation resulted in significant (p<0.05) increase in DMI, body weight gain and plasma GH. The mRNA expression of IGF-1 was significantly (P<0.01) higher in Treatment I.When the groups were compared during hot dry, hot humid and thermo-neutral season, expression of interleukins (IL-6 and IL-10) showed opposite pattern and expression of MnSOD showed similar pattern. The messenger RNA (mRNA) and protein expression of IL-6 was observed to be higher (P<0.01) in control group than Treatment I and Treatment II group and expression of IL-10 and MnSOD were observed to be higher (P<0.01) in Treatment II followed by Treatment I as compared to control. Plasma level of Acute Phase proteins (Serum amyloid A and haptoglobin) and Total Antioxidant capacity were significantly (p<0.05) lower in betaine supplemented groups as compared to control whereas plasma level of cortisol did not differ significantly. In conclusion, betaine administration enhances nutrient utilisation and have a dwindling effect on expression of cytokines, suggesting a possible role of this potent antioxidant immunomodulator on heat stress amelioration. Keywords: Heat stress, Betaine, growth performance, cytokines, immune modulator, antioxidant 1. Introduction The global change in the environment has drawn the attention of researchers to minimize its adverse effect on animal productivity. When the environmental temperature exceeds the body temperature begins to absorb heat, increasing its body temperature from normal to hyperthermia state, leads to heat stress. The productivity of livestock is adversely affected by extreme climatic conditions as well as with different feeding regimens. Reduction in feed intake and production is the common sign of heat stress and different physiological as well as biochemical parameters are also used as an indicator of heat stress. Proper understanding the relationship among climatic factors and feeding regimens will provide a firm basis to improve the health and welfare of animals. Hyperthermia results in redistribution of blood to the periphery and compensatory reduction in the blood supply to the gut, which damages cells lining the gut, leading to endotoxin production in the body. Endotoxin causes tissue damage and acute–phase immune responses. When blood supply resumes, reactive oxygen species and cytokines are released and cause multiple organ injury. Betaine would impact beneficially at several critical points in the progression of thermally induced tissue damage. These include amelioration of damage to gut and liver tissue, and protection against the effects of endotoxin. Thermo-tolerance in animals during prolonged heat stress is characterized by the immunological response and adaptations associated with acclimatization. It is proposed that administration of betaine to livestock would act as an antioxidant, immune-modulator phytogenic feed additive. The immunological response confers transient thermal tolerance, in part due to the expression of Interleukins (IL’s). Cytokines are produced in response to a wide