Lysine and zinc chelate in diets for brown laying hens: effects on egg production and composition

Abstract

-It was evaluated the effects of levels of digestible lysine and chelate zinc combined in the diet for laying on the egg quality. It was used 720 birds, from 48 to 60 weeks of age, distributed in a completely randomized design in a 3 × 5 factorial scheme with three levels of zinc and five levels of lysine, applied into six replicates in the experimental units of eight birds per plot. The levels were: 137, 309 and 655 ppm zinc and 0.482, 0.527, 0.582, 0.644 and 0.732% digestible lysine. It was not observed any interaction among digestible lysine and zinc for the primary variables of fractions and egg composition. Levels of zinc reduced egg weight, suggesting the lowest efficiency in nutrient intake. At the highest dietary concentration of zinc, the addition of digestible lysine coincided with a linear increase in shell weight. However, zinc addition, regardless of lysine level in the diet, resulted in the reduction of egg weight and of the percentage of mineral matter in the yolk, limiting the efficiency of mineral deposition in this fraction of the egg. Concentration of zinc that produced the best results was 137 ppm inasmuch as higher quantities limit the use of digestible lysine, with effects harming composition and egg quality. The study indicates the following requirement for digestible lysine: 0.639% from the 48 th to the 52 nd week, 0.679% from the 52 nd to 56 th week, and 0.635% from the 56 th to the 60 th week. Considering the total period from 48 th to the 60 th week, the level 0.638% of lysine or the daily intake of 707 mg of the amino acid met the requirement for egg quality of semiheavy layers used in this study.

Standardized ileal digestible lysine requirement of white commercial layers in peak egg production

“…The 58% increase in SID Lys intake is related to the dietary SID Lys concentration and to the 6% increase observed on feed intake as SID Lys supply ranged from 6.0 to 9.0 g/kg diet. Similar results were reported by Trindade Neto et al (2011) and Kakhki et al (2016).…”

“…Feed intake could also have influenced the behavior of egg production responses, once more nutrients were consumed when SID Lys content in diets was increased. Likewise, Trindade Neto et al (2011) reported higher feed intake and egg production in hens given diets with higher SID Lys content. The authors estimated the nutritional needs of 24-to -28-wk-old brown commercial layers for optimum egg production at 8.05 g SID Lys/kg diet.…”

“…This increase in egg weight could be related to the higher crystalline amino acid concentration in diets with higher SID Lys content, since essential amino acid supply was concomitantly increased with SID Lys. Once added to diets, essential amino acids like lysine, methionine and tryptophan lead to an increase in egg weight by improving yolk weight and albumen weight (TRINDADE NETO et al, 2011;BRUMANO et al, 2010;CALDERANO et al, 2012).…”

“…The increase observed on yolk weight could be explained by the more precise meeting of hen nutritional needs for amino acids, which could have enhanced the efficiency of nitrogen utilization and, therefore, provided higher net energy amount to yolk synthesis. Lysine supply may enhance both protein (Prochaska et al, 1996) and lipid accretion in yolk (Trindade Neto at al., 2011).…”

Dietary intake of broiler breeder hens during the laying period affects amino acid and fatty acid profiles in eggs

“…Lima et al (2007) reported that different dietary components can affect the characteristics of eggs of commercial laying hens. Besides, Trindade Neto et al (2011) showed that increasing dietary lysine concentration can reduce the protein content and increase the composition of lipids in eggs. Corduk and Sarica (2008) showed that dietary metabolizable energy (ME) levels or fat sources in layer diets significantly affect egg quality parameters.…”