Vitaminas D e C para poedeiras na fase inicial de produção de ovos

Abstract

RESUMO -Um experimento foi conduzido com o objetivo de avaliar os efeitos de duas fontes de vitamina D e três níveis de vitamina C sobre as características de desempenho, a qualidade interna e externa dos ovos, os níveis de cálcio total e iônico séricos e a resistência óssea de poedeiras. Foram utilizadas 288 galinhas da linhagem ISA Babcock B300 ® com 23 semanas de idade, durante um período experimental de 12 semanas. Utilizou-se o delineamento inteiramente ao acaso em arranjo Vitamins D and C for laying hens at the initial phase of egg production ABSTRACT -An experiment was conducted to evaluate the influence of two vitamin D sources and three vitamin C levels on performance, internal and external egg quality, and bone strength characteristics. In addition, the total and ionic blood calcium concentrations, bone ash and calcium were determined. Two hundred and eighty eight 23-week-old ISA Babcock B-300 ® laying hens were used during the 12-week study in a 2 × 3 factorial arrangement: vitamin D sources (cholecalciferol and 25-hydroxycholecalciferol -25(OH)D 3 ) and vitamin C levels (0, 100 and 200 ppm) resulting in six treatments with eight replicates of six hens each. The basal cholecalciferol level was 2,756 IU/kg, corresponding to 5.51 g Hy.D ® /t, as source of 25(OH)D 3 . Feed intake, egg production, egg weight and egg mass were not influenced by the treatments. An interaction was observed for feed conversion, which was improved when 25(OH)D 3 was added without vitamin C. Haugh unit and yolk index were not influenced, however, interactions were observed for albumen percent and yolk percent, which were improved when 200 ppm of vitamin C was supplemented. Egg specific gravity, serum calcium, bone ash and bone strength resistance were not influenced by the treatments. There was an interaction for shell percent and shell thickness, which were improved when vitamin C was added in association with 25(OH)D 3 . It was concluded, for laying hens at initial phase of egg production, that feed conversion is improved when 25(OH)D 3 was the vitamin D source, and that shell thickness and shell percent are improved when the vitamin D source was 25(OH)D 3 with diets supplemented with vitamin C (100 or 200 ppm, respectively).Key Words: ascorbic acid, bone strength, egg quality, performance, vitamin D IntroduçãoA obtenção de bons índices zootécnicos de desempenho e qualidade externa dos ovos geralmente resulta em sucesso para o setor produtivo de ovos comerciais. Reconhece-se que a idade é determinante do desempenho e da qualidade interna e externa dos ovos (Faria et al., 1999a). Estima-se que a incidência de ovos quebrados R. Bras.

Effect of supplementation of diets for quails with vitamins A, D and E on performance of the birds and quality and enrichment of eggs

“…However, the egg weight was not influenced by the levels of vitamin D 3 supplied to birds. Results presented in this experiment for food conversion differ from the ones found by Salvador et al (2009), who found better values for food conversion when laying hens were fed with the metabolite 25(OH)D 3 without the inclusion of vitamin C.…”

“…When evaluating the effect of two sources of vitamin D (cholecalciferol and 25-hidroxicholecalciferol) and three levels of vitamin C (0, 100 and 200 ppm), Salvador et al (2009) observed that the higher percentage of albumen was observed when diets were supplemented with 200 ppm of vitamin C in association to cholecalciferol. However, for the percentage of yolk, the higher value was verified when supplemented with 200 ppm of vitamin C in association to metabolite 25 (OH)D 3 .…”

Combinations of cholecalciferol and 25-hydroxycholecalciferol as vitamin D sources in white laying hen feed diets

“…These results are similar to those found by Hernandez et al, (2001), who reported increased eggshell thickness using a source of vitamin D composed of D 3 and 25-OHD 3 . By contrast, Salvador et al, (2009) established that there are no differences in the yolk, white, eggshell, specific gravity, and eggshell thickness percentage using any of the isolated sources, a conclusion that confirms the results obtained in this study. The increase in eggshell percentage was also generated by BD1, which is a similar finding to that reported by Keshavarz (1998), who observed an increase in eggshell when the Ca consumption increased from 3.51 g to 4.25 g per hen daily.…”

“…Keshavarz (2003), found no difference in the ash percentage when experimenting with 25-OHD 3 (as an isolated source) and different concentrations of Ca and avaP in the diet. This result was confirmed by Salvador et al (2009),who also discovered that the percentage of Ca in the tibias of egglaying hens increases when D 3 is used as the only source of vitamin D. That finding was not observed in this study, as the percentage of Ca in the tibia was the same using all evaluated sources of vitamin D, contrasting with the increase observed with BD1. Schreiweis et al, (2003) observed that the mineral content and bone density of tibias decrease linearly with reduced Ca consumption.…”

“…The effect on feed intake explains the improved feed conversion and agrees with the results found by Brito et al (2010), who determined that the combined use of these same sources of vitamin D improves the productive performance of broiler chickens in all phases of production. Other researchers have utilized isolated D 3 and 25-OHD 3 in diets for egg-laying hens, reporting different effects of 25-OHD 3 as an isolated source of vitamin D; Salvador et al (2009), found improved feed conversion using 2756 IU/kg vitamin D, and Keshavarz (2003), reported no significant effect on the performance of egg-laying hens using 2760 IU/kg vitamin D. In another experiment, Hernández et al (2001), used 2750 IU/kg D 3 to meet the vitamin D requirements of egg-laying hens and also supplemented with 2760 IU/kg 25-OHD3 without observing effects on the productive performance of the assessed birds.The studies mentioned above used higher levels of vitamin D, which is necessary for further testing of the association between sources at various levels of dietary supplementation. Importantly, the NRC (1994) BD1, taking into account the feed intake, allowed the daily consumption of 4.1 g of Ca and 0.39 g of avaP per bird, which is an amount similar to that suggested by the Dekalb White 2009 (Institut de selection animale B.V., 2009) management guide (4.2 g Ca/bird/day and 0.44 ava P/bird/day) and to the recommendation by Rostagno et al, (2005) of 4.02 g Ca with 0.37 g avaP bird/day for white hens in production.…”