Manipulation of plasma myo-inositol in broiler chickens: effect on growth performance, dietary energy, nutrient...

This study investigated the effects of graded levels of myo-inositol (INS) in diets containing 2 levels of available P on growth performance, nutrient retention, liver N, fat and vitamin E contents, INS and alkaline phosphatase (ALP) concentrations in blood plasma. A total of 120 male Ross 308 broilers were allocated to 60 small floor pens each holding 2 birds. Two basal mash diets were formulated to be nutritionally adequate for chicks at that age, with one diet designed to have the recommended available P content (RP) (4.8 g/kg non-phytate P) and the other diet containing low available P (LP) (2.5 g/kg non-phytate P). The 2 basal diets were split in 3 batches each and 2 of the batches were supplemented with INS at 3.0 and 30 g/kg diet, with the remaining batch of each basal diet not supplemented, giving a total of 6 experimental diets. Diets were fed ad libitum to 10 pens from 7 to 21 d age following randomization. Feeding RP diets improved (P < 0.001) the birds' growth performance, mineral availability, and blood plasma ALP. Feeding RP diets reduced (P < 0.001) apparent metabolizable energy (AME), dry matter and fat availability, blood plasma INS, and hepatic vitamin E. Dietary INS did not (P > 0.05) influence bird growth, dietary AME, or nutrient retention coefficients. Feeding INS linearly increased (P < 0.05) liver weight and hepatic N content, but linearly reduced (P < 0.05) hepatic fat concentration. It also linearly increased (P < 0.001) the INS concentration in blood plasma, but did not influence (P > 0.05) the endogenous losses (measured as sialic acid concentration) in excreta. Dietary INS did not influence (P > 0.05) the hepatic vitamin E concentration but increased (P < 0.001) the ALP in the blood of birds fed 30 g/kg INS. In conclusion, high-level dietary INS supplementation did not affect bird growth performance, mineral availability, and endogenous losses, and there were no interactions between INS and P.