Sodium gluconate and methionine sources on performance, intestinal morphometry and bone densitometry on broilers of 22 to 42 days of age

Methionine is the first limiting amino acid in diets used for broilers; an alternative is the use of synthetic amino acids. Sodium gluconate is considered as a prebiotic because it stimulates the production of butyrate and can have the purpose of increasing methionine absorption. The literature is, however, not conclusive on the benefits of sodium gluconate, reason for which studies on this additive are important. Two experiments were conducted in order to evaluate the effects of sodium gluconate added to a) two methionine sources, i.e. DL-Methionine (DLM) and methionine hidroxy analogue (MHA), and b) three levels of MHA (normal, reduction of 10% and 20%), on performance, carcass yield and carcass composition, intestinal morphometry and bone densitometry of broilers 22 to 42 days of age. Both experiments used male COBB^(R) 500 broilers, distributed in a completely randomized design on factorial scheme 3 x 2 (three levels of methionine+cistyne x two levels of sodium gluconate); to study the effects of sodium gluconate on the two methionine sources, a factorial scheme 2 x 2 (two levels of sodium gluconate and two sources of methionine) was adopted. All variables were submitted to the analysis of variance and the means compared by the TTukey test at 5% of probability. It was concluded that: (1) the use of the two sources of methionine proved their viability without diminishing the birds' performance; (2) the methionine hidroxy analogue level 0.77% resulted in the birds' best performance, confirming that methionine is an essential amino acid and its deficiency reduces performance; (3) gluconate did not affect bone density of birds; (4) the supplementation of (2000 ppm) of sodium gluconate improved the intestinal integrity, a tendency for improvement of the other variables was observed, evidencing the necessity of further studies with different levels of this additive.