Effects of balanced dietary protein levels on egg production and egg quality parameters of individual commercial layers

Abstract

The effects of a series of balanced dietary protein levels on egg production and egg quality parameters of laying hens from 18 through 74 wk of age were investigated. One hundred forty-four pullets (Bovans) were randomly assigned to individual cages with separate feeders including 3 different protein level series of isocaloric diets. Diets were separated into 4 phases of 18-22, 23-32, 33-44, and 45-74 wk of age. The high protein (H) series contained 21.62, 19.05, 16.32, and 16.05% CP, respectively. Medium protein (M) and low protein (L) series were 2 and 4% lower in balanced dietary protein. The results clearly demonstrated that the balanced dietary protein level was a limiting factor for BW, ADFI, egg weight, hen day egg production (HDEP), and feed per kilogram of eggs. Feeding with the L series resulted in lower ADFI and HDEP (90.33% peak production) and more feed per kilogram of eggs compared with the H or M series (HDEP; 93.23 and 95.68% peak production, monthly basis). Egg weight responded in a linear manner to balanced dietary protein level (58.78, 55.94, and 52.73 g for H, M, and L, respectively). Feed intake of all hens, but especially those in the L series, increased considerably after wk 54 when the temperature of the house decreased due to winter conditions. Thus, hens fed the L series seemed particularly dependent on house temperature to maintain BW, ADFI, and HDEP. For egg quality parameters, percent yolk, Haugh units, and egg specific gravity were similar regardless of diets. Haugh units were found to be greatly affected by the variation of housing temperature (P = 0.025). Maximum performance cannot always be expected to lead to maximum profits. Contrary to the idea of a daily amino acid requirement for maximum performance, these results may be used to determine profit-maximizing levels of balanced dietary protein based on the cost of protein and returns from different possible protein levels that may be fed.

Phytase and protease supplementation for laying hens in peak egg production

“…Because the weight of the eggs from the hens fed protease B was lower than that of the eggs from positive-control hens, we can assume that only the lower albumen height of the protease-B hens was responsible for its lower Haugh unit value, since egg weight is negatively associated with the Haugh unit while albumen height is positively associated. Contrary to our results, Shim et al (2013) described an increase in the Haugh unit after reduction of dietary crude protein. This response was probably a consequence of the lower egg weight; nevertheless, because the albumen height was not provided by the authors, our comparison remains limited.…”

“…While different assumptions could be made to explain the better performance by protease A, the results of all treatments led to one big question: does protease A alone have a more suitable nutritional matrix than protease B alone, or is the actual nutritional contribution of the combination of protease A and phytase greater than the nutritional contribution of protease alone? Because different levels of interaction between phytases and multienzyme complexes with proteases have been described for broilers and hens (AL-SAFFAR et al, 2013;OLUKOSI et al, 2010;TIWARI et al, 2010), it seems reasonable to consider the second option as a valid statement. In this case, increased or decreased affinity between enzymes under study may be responsible for the different responses observed for each protease.…”

“…Proteases alone have only started to be evaluated in recent years, as they were usually analyzed as part of multienzyme complexes, combined with xylanases, amylases, and glucanases (ADEOLA; COWIESON, 2011). Studies comparing the effects of these complexes in addition to phytases are abundant in the literature (AL-SAFFAR et al, 2013;OLUKOSI et al, 2010;TIWARI et al, 2010), but most of them were conducted with broilers. Therefore, although some improvement in performance and feed digestibility has been described in birds fed with proteases, assumptions about the combined effects of proteases and phytases that do not take into account the presence of carbohydrases, or that are related to egg production and egg quality parameters, still require further investigation.…”

Effects of Protein in Diet and Sex Ratio on Egg Production, Egg and Hatching Chick Weight, Fertility, Hatchability and Embryonal Mortality in Pheasants (Phasianus Colchicus)

“…Some researchers reported the general tendency increase egg production and egg weight with the increase of protein levels in the diets (Gunawardana et al, 2008;King'ori et al, 2010;Mohiti-Asli et al, 2012;Shim et al, 2013). Some other researchers reported that egg production and egg weight was not affected by feeding low crude protein (Cho et al, 2004;Khajali et al, 2008).…”

“…The composition of hen diet has an effective factor on egg production (Khajali et al, 2008;Perez-Bonilla et al, 2012), egg weight (Whitehead et al, 1991, Zimmerman 1997Shim et al, 2013) and hatching characters (Danicke et al, 2000) in poultry.…”