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Role of Betaine in Poultry Production Pratik Rajaram Jadhav, Amitav Bhattacharyya and Pankaj Kumar Shukla Department of Poultry Science, College of Veterinary Science and Animal Husbandry, DUVASU, Mathura (U.P.), India
Modern intensive poultry production has attained phenomenal progress in the efficient and economical production of quality safe meat and eggs. High ambient temperature is one of the most i m p o r t a n t p ro b l e m s f o r p o u l t r y production in many regions of India. Prolonged heat stress reduces visceral blood supply to the intestine and causes damages to epithelial cells in the gut there by affecting feed digestion and nutrient absorption (Cronje, 2007). It may also disrupt intestinal barrier increasing the likelihood of pathogenic bacteria and endotoxin entry, which can then result in excessive inflammation, decreasing production performance and possibly death (Quinteiro-Filho et al., 2012). Heat stress has negative impact on poultry production. Using feed additives having positive effects for resisting thermal stress may be a viable solution. Betaine has many important functions in the health and performance of broiler chickens, especially under conditions of heat stress. Betaine in reaction with the homocysteine has methionine saving effect, where it donates methyl group instead of methionine (Paniz et al., 2005). Betaine is an osmolyte and assists in cellular water homeostasis (Klasing et al., 2002). Betaine supplementation in feed improves growth performance and feed intake under heat stressed condition (Hassan et al., 2005). The positive effect of betaine is due to the fact that it reduces the body temperature in chickens (Klasing et al., 2002). Betaine as a natural plant extract has long been a known functional nutrient in poultry nutrition. Chemically, N,N,NTrimethylglycine (TMG) is a neutral, zwitterionic, quaternary ammonium compound. This naturally occurring phytogenic feed additive compound is exceptionally high in sugar beet, also
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present in other plants viz. wheat, oat, barley etc. and in animals and seafood. Betaine was in the past mainly used as betaine anhydrous extracted from sugar beets; but, now it is available as betaine hydrochloride or betaine monophosphate, which is synthetically produced. Use of betaine as a feed additive in the poultry diet is one of the nutritional strategies for reducing stress in the broiler. It acts as a methyl donor through methionine recycling and as an osmolyte that helps in maintaining the cellular water balance which support animals to cope with water-related stress conditions (dehydration, diarrhoea, etc.) as well as helps reducing litter moisture that aids to overcome coccidiosis and stress. Besides, betaine has multiple functions: preser ves gut integrity, improves carcass quality, spares choline and reduces the inclusion of methionine and increases nutrient digestibility. It can also be a lipotropic agent, causing reduction of back-fat to otherwise fatty animals (such as castrates), and can improve performance, notably feed efficiency. Absorption and metabolism Betaine is rapidly absorbed in the duodenum. Absorption of betaine is more rapid than choline or methionine. Choline and methionine are associated with plasma lipoprotein, whereas betaine remains in a free state in the plasma. It has 25% bioavailability, while 75% of it could remain at GIT intracellular level. Intracellular accumulation takes place via active ( N a + o r C l - ) a n d pa s s i ve ( N a + ) transport systems. Betaine is eliminated by metabolism, not by excretion, and catabolized via a series of enzymatic reactions that occur in the mitochondria of liver and kidney cells.
Methyl group metabolism Methyl groups are of vital importance in the metabolism of all animals, besides, animals cannot synthesize methyl groups and thus need to receive them in their diets. The methyl groups are used in methylation reactions to remethylate methionine and to formulate useful compounds such as carnitine, creatine and phosphatidylcholine through the Sadenosyl methionine pathway. Carnitine is required for transport of long-chain fatty acids across the mitochondrial membrane for oxidation. To generate methyl groups, choline can be oxidised to betaine within the mitochondria. Dietary requests of choline can be covered from choline present in (vegetable) raw materials and by the syntheses of phosphatidylcholine and choline once there is availability of Sadenosyl methionine. Regeneration of methionine occurs by betaine donating one of its three methyl groups to homocysteine, via the enzyme betainehomocysteine methyltransferase. After donation of the methyl group, one molecule of dimethylglycine (DMG) remains, which is oxidised to glycine. Betaine supplementation has been shown to reduce homocysteine levels while resulting in modest increases of plasma serine and cysteine levels. This stimulation of betaine-dependent homocysteine remethylation and the subsequent decrease in plasma homocysteine can be maintained as long as supplemental betaine is taken. In general, animal studies show that betaine can replace choline chloride with higher efficacy and can replace part of total dietary methionine, resulting in a cheaper diet for maintaining performance. Florou-Paneri et al. (1997) showed that between 30% and 80% of the supplemental methionine can be substituted by betaine without negative
Poultry Planner | Vol. 22 | No.09 | November - 2020
