Effects Of Supplemental Zn-Met On Performance And No-specific Immunity Of Layer In Final Phase

Zn is an indispensable trace element to animals that finish growth, development and reproduction. It has been hitherto a zealous task for scholars of pasturage to supplement animals with enough Zn. Met is the first restrictive amino acid in the feedstuff of poultry, while Zn is the most important, versatile trace element. Therefore, the Zn-Met who is undoubtedly the high efficient , secure, steady resources of Zn should be favoured.The researchs of Zn-Met were comparatively lack in layer, and were concentrated in the former, middle phase, the report with regard to entire effect of Zn-Met supplementation in diet on layer was not found. Author analyses the reason of different effect of Zn-Met, consider vitamin E and NaSO,, widely used in current feeding. The abroad research aiming at combination Zn~Met with vitamin E and NaS04 should be significant.The paper investigated the effect of different resources of Zn and different levels on layer diet through feeding test, quality of egg shell test, slaughter test, immunological test, tissue observation and so forth, moreover supplied a few significant references in order to combination of Zn-Met and vitamin E, etc.216 57-week-old health hylane browns were randomly arranged to 9 groups with 4 replicates and 6 for each replicate. The trial was designed to 3 resources of Zn (ZnS04 and Zn-Met and combination of Zn) x3 levels (40mg/kg and 70 mg/kg and 100 mg/kg), the maize-soybean diet was formulated as recommended by Nation Standard (1986).The results of the experiment are as follows:1. Performance: Supplemental 70mg/kg Zn significantly increased egg-producing rate (P<0.05); Zn-Met and 40mg/kg Zn can significantly enhanced feedstuff efficiency (P<0. 05); besides decreased broken eggs rate (P<0. 01). Other effect of indexes on performance were not found.2. Egg shell quality: Supplemental Zn-Met in layers diet enhanced the intensity of egg shell (P<0.05).3.Physiological and biochemical parameters: 40mg/kg Zn significantly increased Zn content in eggs (P<0.01); resources of Zn and levels of Zn had obvious interactions in content of Zn in eggs; other changes of physiologicaland biochemical parameters were not significant.4. No-special immunoassay: Supplemented Zn-Met in layers diet could enhance T lymphocyte transformation index (P<0. 01). 70mg/kg Zn could increase IgG content in plasma (P<0. 05).5. Tissue observation: Supplemental Zn~Met and combination of Zn in layers diet could obviously enhance integrality of epithelium of small intestine and of trachea; improve structure of the epithelium and cilia; in the trial, all kinds of resources of Zn did not significantly affect structure of the Fallopian tube.