Soner Cankaya

Performance, carcass, gastrointestinal tract and meat quality traits, and selected blood parameters of broilers fed diets supplemented with humic substances

BACKGROUNDnThe effects of humic substances (HS) on quality traits (colour, water-holding capacity, and pH) of breast and thigh meats and on blood minerals (calcium and phosphorus) and on metabolites (glucose, total protein, triglyceride and cholesterols) as well as on the performance, carcass, and gastrointestinal tract (gut) traits of broilers were studied. In total, 480 male chicks (ROSS 308) were allocated to four treatments, each with five replicates containing 24 birds. While control birds were fed a diet (mash form) with no additives (0 HS), other treatment birds were fed with diets containing HS at 0.5 (0.5 HS), 1.0 (1 HS) or 1.5 (1.5 HS) g kg(-1) from 1 to 42 days of age.nnnRESULTSnThe body and carcass weights and feed efficiency increased (P < 0.05) by 1.5 HS, and blood cholesterol decreased (P < 0.05) by 1 HS and 1.5 HS compared to 0 HS. The 0.5 HS decreased (P < 0.10) low-density lipoprotein compared to 0 HS. The 0.5 HS resulted in thigh meat and breast meat that were lighter and darker than those found in the other groups and 1.5 HS respectively (P < 0.01).nnnCONCLUSIONnFeeding with a diet containing HS caused a measurable variation in the meat quality and blood cholesterol as well as the performance, carcass, and gut traits of broilers.

A Comparative Study of Estimation Methods for Parameters in Multiple Linear Regression Model

Abstract Cankaya, S., Kayaalp, G.T., Sangun, L., Tahtali, Y. and Akar, M. 2006. A comparative study of estimation methods for parameters in multiple linear regression model. J. Appl. Anim. Res., 29: 43–47. This paper investigated least squares method, non-parametric method and robust regression methods to predict the parameters of multiple regression models. To evaluate these methods, measurements of body weight, total length and fork length of fishes collected from Serranus cabrilla were used. In these regression models, body weight was dependent variable whereas total length and fork length were independent variables. The results show that non-parametric regression method, general additive model, has minimum R2 value and least median squares has maximum R2 value, 0.334 and 0.855, respectively.

Response of two catchweed bedstraw (Galium aparine) populations to post-emergence herbicides in winter wheat

Catchweed bedstraw causes severe problems in winter wheat and other winter sown crops. Field experiments were conducted from 2005 to 2008 in wheat fields in Samsun, Turkey, to determine: (1) the response of catchweed bedstraw to chlorsulfuron, tribenuron-methyl plus thifensulfuronmethyl, dicamba plus triasulfuron and mesosulfuron-methyl plus iodosulfuron-methyl-sodium; and (2) possible resistance or tolerance to these herbicides. The herbicides were applied at the 2–4, 4–6, and 6–8 true leaf stages of biomass, there were large differences among the upper limits of the dose-response curves, and consequently, the actual response curve, an asymmetric sigmoid curve, was fitted to data to obtain 50% and 90% effective dose, ED50 and ED90, values. None of the herbicides reduced catchweed bedstraw biomass or populations satisfactorily when applied at the recommended field rate. Twice the recommended field rate was required to achieve acceptable reduction in biomass. Overall, inadequate control of this weed cannot be solely attributed to either acetolactate synthase (ALS) resistance or improper application methods. It is likely due to a slow and progressive development of ALS-tolerant populations after many years of consecutive use.