Abstract
A study was conducted to evaluate citric acid (CA) as an additive in poultry broiler diet with lower mineral density of calcium and phosphorus in commercial broiler poultry birds under complete randomized design. For this purpose, Vancobb-400 strain day old broiler chicks (n=320) were divided into 4 main treatment groups T0, T1, T2 and T3. Each treatment group was further divided into8 replicates with 10 chicks in each. T0 served as control diet and was given standard corn- soy flake based ration(Pre-starter%; CP;Ca;TP--23,1.00,0.70, Starter;22,1.10,0.72 and Finisher;20,0.99.70)and treatment T1 served as standard ration with added 0.5 per cent CA with no change in chemical composition (Pre-starter %; CP;Ca;TP23,1.00,0.70, Starter; 22,1.10,0.72 and Finisher;20,0.99.70). Treatment T2 was given standard cornsoy flake based ration containing 0.5 per cent CA with low calcium (Ca) and total phosphorus (TP) content (Pre-starter %; CP;Ca;TP --23,0.90,0.66,Starter; 22,0.99,0.71 and Finisher;20,0.90,0.69)whereas treatment T3 was given standard corn- soy flake based ration containing 0.5 per cent CA with moderately low calcium (Ca) and total phosphorus (TP) content(Pre-starter %;CP;Ca;TP--23,0.80,0.65,Starter;22,0.88,0.70 and Finisher;20,0.79,0.68)as per ICAR (2013) standards. Perusal of the results revealed that broiler birds offered moderately low Ca and TP exhibited higher growth performance (P<0.05) for gain in weight, feed intake, feed conversion efficiency and carcass traits viz. dressing percentage and forequarters weight. Addition of 0.5 per cent CA in low and moderately low Ca and TP offered diets conferred protection to birds by lowering mortality in birds through reduction in total microbial count in the lower gastro intestinal tract. Results of the experiment revealed activation of homeostatic mechanisms in birds offered moderately low Ca and TP with added 0.5% CA modulating enhanced availability of calcium and phosphorus as evident in metabolic trial, blood and tibiae bone studies but the homeostatic mechanism was less pronounced when Ca and TP density in diet was low. Overall economics exhibited lowest cost of producing, per kg live weight in broiler birds offered moderately low Ca and TP with added 0.5 % CA. In conclusion, birds offered corn soya based diet with moderately low mineral viz. calcium and total phosphorus as per ICAR 2013 standard with added 0.5 per cent citric acid can enhance the growth, improve carcass characteristics and improve the FCR of broilers though favourable environment in lower intestinal tract and activation of homeostatic mechanisms of calcium and phosphorus digestion and absorption, thus economizing the cost of production.
The in vitro metabolism of 25-hydroxycholecalciferol by pig kidney: effect of low dietary levels of calcium and phosphorus
