Behzad Barghi - Department of Animal Science, Faculty of Agriculture, University of Zabol, Zabol, Iran
Mohammad Rokouei - Department of Animal Science, Faculty of Agriculture, Tarbiat Modares University, Tehran, Iran
Ali Maghsoudi - Department of Animal Science, Faculty of Agriculture, University of Zabol, Zabol, Iran
Hadi Faraji-Arough - Department of Ostrich, Special Domestic Animals Institute, Research Institute of Zabol, Zabol, Iran

Lysozyme activity is one of the nonspecific immunity parameters measured by changing the amount of adsorption at different times. The objective of the present study was to compare five non-linear models including Gompertz, Richards, Logistic, Lopez, and Weilbull to describe the cumulative plasma lysozyme activity in quails. In total ۱۳۶۴ plasma samples (۱۰۰۴ females and ۳۶۰ males) were collected and the cumulative lysozyme activity was calculated by turbidimetric method assay in Micrococcus luteus. The goodness-of-fit of models was compared according to different criteria of Maximum log-likelihood, Akaike information criterion, Mean square error, and Bayesian information criterion. The results showed that the Gompertz model was the best model for describing of decreasing cumulative pattern of lysozyme activity in female and male quails and provided satisfactory predictions of lysozyme activity at different times (۳۰, ۶۰, ۹۰, ۱۲۰, ۱۵۰, ۱۸۰, ۲۱۰, ۲۴۰, ۲۷۰, ۳۰۰ seconds). The parameters of all models were higher in females than males except for the k parameter which was greater in the males. Male quails had higher values for time and lysozyme activity than females at inflection points, whereas the absolute growth rate in ۳۰, ۱۵۰, and ۳۰۰ seconds was predicted higher in female quails. In conclusion, the Gompertz model can be used accurately to evaluate cumulative lysozyme activity patterns in both sexes of quails.

Quail, Immunity, Non-linear models, Inflection point