مقايسه زيست فراهمى منابع تجارى مختلف كولين در جوجه هاى گوشتى

Application

An evident concept is that choline bioavailability is <100% in corn-soybean meal diets, but choline is essential for prevention of fatty liver and perosis in poultry.

Introduction

It has long been Nnown that chicNens fed corn-soybean meal diets containing choline in excess of the NRC (1994) requirement, still need supplemental choline to achieve maximum growth (Marvel et al. 1943). The aim of the present study was to evaluate three commercial sources of choline (product of Belgium (CHO1), China (CHO2) and Germany (CHO3) for broiler chicNen.

Material and methods

Two hundred female broiler chicNens (Ross 308) reared in a 42 days trial. Ten dietary treatments included three dietary added levels of choline (400, 800 and 1200 mg/Ng) to the basal diet (contained 862 mg choline/Ng). Birds received experimental feed ad libitum. Treatments replicated 4 times each included five chicNens in a completely randomized design. Performance (body weight gain and feed conversion ratio), carcass characteristics (breast, thighs, liver and abdominal fat fractional weight), liver fat content, different fatty acids (palmitic acid, oleic acid, linoleic acid, palmitoleic acid : stearic acid) in liver fat content and also bone physical properties were compared statistically. Data were analysed using the GLM procedure of SAS. Duncan’s multiple range test was used to determine differences among treatment means at P<0.05. Relative bioavailability values of choline were estimated using CHO2 as the standard source by slope ratio comparison from multiple linear regressions (Little et al., 1997).

Results

Performance, carcass and bone characteristics had no significant difference between sources of commercial choline. Relative bioavailability of mentioned sources of choline did not show significant difference (Table 1).

Table 1

Relative bioavailability values (RBV) of choline sources (CHO1 and CHO3) in comparison with reference source (CHO2) based on slope ratios from linear regressions of feed conversion ratio, liver fat content, palmitoleic acid:stearic acid and bone strength on added levels of choline to basal diet at 42 days of age Dependent variable Choline

Conclusion

It is not necessity to add excess sources of choline to corn-soybean meal diets with low levels of metabolizable energy (ME) and crude protein (CP), because of same performance (P>0.05) of birds which received different levels of choline. The re-evaluation of choline requirement of broiler chicNens offered corn-soybean meal diets with high levels of ME and CP is recommended to achieve optimum performance.

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