Reevaluation of Methionine Requirement Based on Performance and Immune Responses in Broiler Breeder Hens

Abstract

This experiment was conducted to study methionine requirements in broiler breeder hens aged from 26-35 weeks. The treatments were consisted of six levels of methionine (0.2, 0.25, 0.3, 0.35, 0.4 and 0.45%), with five replicates of eight birds (Seven hens and one rooster). The results showed that different levels of methionine had no significant ( p＞0.05) effects on egg weight, unsettable (double yolk, small size) and settable eggs. The methionine levels significantly ( p＜0.05) changed egg production percentage, egg mass (g/h/d), egg content (g) and feed conversion ratio. Different levels of methionine did not affect on cell-mediated responses, newcastle and bursa diseases titer, and IgM ( p＞0.05), but total titer against sheep red blood cell (SRBC) and IgG responses were influenced (p＜ 0.05). Using of two-slope quadratic broken-line analysis indicated that methionine requirements for egg mass (g/h/d), feed conversion ratio, settable eggs, SRBC and IgG were 446, 450, 494, 580 and 492 (mg/d), respectively. In conclusion, methionine requirement for settable eggs was similar to those needed for the optimum immune responses. Since, settable eggs are an important factor in broiler breeder industries, so the authors recommend 494 mg/d methionine for broiler breeder hens. This amount is higher than those needed for egg mass and feed conversion ratio.

Biochemical and immunological responses of young turkeys to vaccination against Ornithobacterium rhinotraheale and different levels of dietary methionine

“…A considerable, but not statistically significant increase was observed in the total serum IgG levels of turkeys from groups MM and HM, vaccinated against ORT, compared with vaccinated turkeys birds from group LM. Our findings are partially consistent with those reported by Hosseini et al (2012) who found no significant differences in serum IgM levels and antibody titers against Newcastle disease virus (NDV) and infectious bursal disease virus (IBDV) in broiler breeder hens fed diets supplemented with methionine at 0.25 -0.45%. The cited authors noted significant differences in the serum levels of IgG and antibody titers against sheep red blood cells (SRBC) and demonstrated that methionine requirements needed for the optimum immune responses were higher than those needed for good performance and productivity.…”

“…Therefore, the methionine requirements of young and fast-growing turkeys should be precisely defined, as both methionine deficiency and excess can compromise the performance and immune system of birds (Tsiagbe et al 1987, Swain and Johri 2000, Deng et al 2007). According to Klasing et al (1988) and Hosseini et al (2012), dietary methionine levels required for immune system competence are higher than those needed to maximize the bird's potential for growth and productivity. The relationship between dietary methionine intake and immune system function has been investigated in numerous studies involving chickens (Tsiagbe et al 1987, Zhang and Guo 2008, Bunchasak 2009) and in our previous experiment performed on 4-week-old turkeys .…”

Effects of dietary methionine on productivity, reproductive performance, antioxidant capacity, ovalbumin and antioxidant-related gene expression in laying duck breeders

“…In this study, dietary Met levels affected the egg weight, egg mass, FCR, hatchability, proportion of healthy ducklings and their weight, but did not affect egg production and fertility. Previously, Xiao et al ( 5 ) found improvements in egg production, FCR, fertility and hatchability after increasing the Met level from 0·25 to 0·35 % in Chinese broiler breeders, whereas Hosseini et al ( 8 ) showed that increasing the Met concentrations from 0·20 to 0·45 % for 8 weeks during the peak laying period in Iranian broiler breeders impaired egg production, egg mass and FCR, but did not affect hatchability, quality of chicks or their weight. In the previous study of Longyan laying ducks from 19 to 47 weeks of age, improvements in egg weight were found after increasing Met level from 0·25 to 0·50 %, but egg production, egg mass and FCR were not affected ( 7 ) .…”

“…The effects of maternal dietary Met on the antioxidant variables measured in hatchlings did not exactly follow the effects noted earlier on maternal traits, nor the hatchability and proportion of healthy ducklings. Previous studies have investigated the effects of dietary Met on breeders, but they generally did not consider its effects on their offspring ( 5 , 8 ) . Indeed, only Brun et al ( 51 ) showed that maternal dietary Met affects the growth performance and lipid metabolism in the offspring of Muscovy duck breeders.…”

“…Dietary Met levels affect the secretion of hormones in animals, such as triiodothyronine, insulin growth factor-II, estradiol, follicle-stimulating hormone and luteinising hormone ( 2 – 4 ) . In avian species, Met deficiency impairs the laying performance, egg mass, feed conversion ratio (FCR) ( 5 – 7 ) , antibody production ( 8 ) and retards female reproductive organ development ( 9 – 11 ) , including relative weight of the ovary, oviduct length, total number of follicles, large and small, and the growth rate of secondary follicles ( 4 ) . Met deficiency can lead to imbalanced lipid and protein metabolism, which reduces egg quality and increases the incidence of reproductive problems associated with fatty liver and obesity ( 10 – 13 ) .…”