Abstract
The objective of this study was to estimate the digestible lysine requirement of Japanese quails in the egg-laying phase. A total of 336 female Japanese quails (Coturnix coturnix japonica) of average initial age of 207 days were distributed in a completely randomized experimental design, composed of 6 treatments (lysine levels) with 7 replicates and 8 birds per experimental unit, with duration of 84 days. Experimental diets were formulated from a basal diet, with corn and soybean meal, with 2.800 kcal ME/kg and 203.70 g/kg crude protein, showing levels of 9.50; 10.00; 10.50; 11.00; 11.50; and 12.00 g/kg digestible lysine; diets remained isoprotein and isocaloric. The following variables were studied: feed intake (FI); lysine intake (LI); egg production per bird per day (EPBD); egg production per bird housed (EPBH); production of marketable eggs (PME); egg weight (EW); egg mass (EM); utilization efficiency of lysine for egg mass production (UELEM); feed conversion per mass (FCEM); feed conversion per dozen eggs (FCDZ); bird availability (BA); percentages of yolk (Y), albumen (A) and shell (S); specific egg weight (SW); nitrogen ingested (NI); nitrogen excreted (NE); and nitrogen balance (NB). Significant effect was only observed for LI, EW, EM, UELEM, FCEM, Y, A and SW. The digestible lysine level estimated in diets for laying Japanese quails is 11.20 g digestible lysine/kg diet, corresponding to an average daily intake of 272.23 mg lysine.
Highlights
The advancements in the knowledge of the nutritional requirements of birds, at their many phases, has constantly brought improvement to the quality of the diet; firstly in the sense of reaching maximum production, followed by the search for the lowest price of the feed and for the conversion of these animals into egg numbers (Ceccantini & Yuri, 2008).the great knowledge of the metabolism of protein in birds and the production of amino acids on a commercial basis have enabled the utilization of the concept of ideal protein at the formulation of diets
According to the values recorded for average air temperature and relative air humidity, throughout the experiment, quails underwent periods of heat stress
The digestible lysine levels did not affect (P>0.05) feed intake (Table 2); these results are similar to those found by Ribeiro et al (2003) and Demuner et al (2009a), who worked with Japanese quails in the laying phase
Summary
Quail raising has stood out in the aviculture sector, especially for egg production, for being extremely attractive and profitable for the Brazilian agribusiness, which makes it a good option, be it for small or big farmers.The advancements in the knowledge of the nutritional requirements of birds, at their many phases, has constantly brought improvement to the quality of the diet; firstly in the sense of reaching maximum production, followed by the search for the lowest price of the feed and for the conversion of these animals into egg numbers (Ceccantini & Yuri, 2008).the great knowledge of the metabolism of protein in birds and the production of amino acids on a commercial basis have enabled the utilization of the concept of ideal protein at the formulation of diets.This concept can be defined, theoretically, as the exact balance of the amino acids in the diet capable of meeting, without excess or deficiency, the requirements of all the essential amino acids for production and maintenance of birds, expressing them as percentage in relation to the lysine which is adopted as reference amino acid.Lysine is the second limiting amino acid in diets for birds; its use, in lower or excessive levels, regarding the nutritional requirement of this nutrient in birds, may bring metabolic damages, which could compromise bird performance (Kidd & Kerr, 1998).For many decades, studies on the utilization of lysine, based on the concept of ideal protein in the diets of birds, have been developed, because of the great applicability, ease of utilization in the formulation of diets and low costs of the acquisition of L-lysine-HCl; in quail raising, these studies are recent.Estimating the digestible lysine requirement for Japanese quails at laying, Pinto et al (2003) suggested the level of 11.17 g digestible lysine/kg of diet for diets containing 195.60 g crude protein (CP)/kg of diet. Rodrigues et al (2007) evaluated the digestible lysine nutritional requirements in diets for Japanese quails in the laying phase and concluded that the digestible lysine requirement was 10.30 g/kg of the diet. The advancements in the knowledge of the nutritional requirements of birds, at their many phases, has constantly brought improvement to the quality of the diet; firstly in the sense of reaching maximum production, followed by the search for the lowest price of the feed and for the conversion of these animals into egg numbers (Ceccantini & Yuri, 2008).the great knowledge of the metabolism of protein in birds and the production of amino acids on a commercial basis have enabled the utilization of the concept of ideal protein at the formulation of diets. Assessing the digestible lysine nutritional requirement in diets for Japanese quails in the laying phase containing 195.0 g CP/kg of diet, Demuner et al (2009a) concluded that the digestible lysine requirement estimated was 10.90 g/kg of diet
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