Effect of replacing soybean meal with lupin seed-based meal in chicken diet on performance, carcass value and meat quality.

The main objective of this experimental study was to determine how diets containing lupin meal affect the performance indicators, carcass value, and chemical composition of breast and thigh muscles in broiler chickens. The diets tested in experimental groups E1 and E2 differed as follows: in group E1, one third of nitrogen-containing substances (NSs) from extracted soybean meal was replaced with NSs from lupin meal; in group E2, two thirds were replaced compared to the control group. The replacement of soybean meal with lupin meal in experimental diets failed to produce any significant effect on the average live weight of chickens on Day 42 of the fattening period compared to the control group. The replacement of soybean meal with lupin meal resulted in decreased average weight of carcass and breast muscles and in decreased yield of breast muscles. Differences between the control group (C) and group E2 were significant (P ≤ 0.01). Chickens in group E2 also showed a significant increase (P ≤ 0.01) in the yield of the heart and stomach compared to the control group. The differences in weight and yield of thigh muscles between the control group and the experimental groups (E1 and E2) were not significantly affected. As far as chemical composition is concerned, chickens receiving the lupin-containing feed showed a significant (P ≤ 0.01) increase in the ash content in breast muscles. On the contrary, in thigh muscles in group E2, the ash content decreased significantly (P ≤ 0.01). The content of calcium showed an increasing trend in both breast and thigh muscles in both experimental groups. In contrast, the content of magnesium in chicken muscles in both experimental groups decreased. These differences were significant (P ≤ 0.01) only in thigh muscles. Our results show that lupin seed is a suitable substitute for NSs contained in soybean extracted meal. It is considered optimal to replace up to one third of NSs contained in soybean meal with lupin seed. Higher inclusion rate of lupin meal in diets may reduce the growth intensity of chickens, particularly the yield of breast muscles. Due to substantial inter-varietal differences, it is necessary to optimize individual nutrients, particularly amino acids when formulating lupin-containing diets. Broiler chickens, weight and yield of organs and muscles, chemical composition of breast and thigh muscles From a nutritional point of view, the seed of cultivars of the genus Lupinus is a proteinenriched raw material used as feed or in feeding mixtures intended for the nutrition of practically all species and categories of farm animals. For these reasons, lupin growing areas in Europe are expanding. In the Czech Republic, growing and using lupin is not as common as in the neighbouring countries. Ecologically speaking, lupins are promoted because most lupin varieties are not genetically modified. The use of lupins in diets for poultry was tested by a number of authors, for example by Schams-Schargh et al. (1994). Their experiment examined the effect of sweet lupins in diets, particularly the variety Amiga, included at 6, 12, and 18% inclusion rate. The authors concluded that there were no significant differences between the groups in the fattening capacity, the percentage of fat, and the percentage of valuable parts of carcass. RothMaier and Kirchgessner (1994) who tested diets containing up to 45% of white lupin arrived at the conclusion that the supplementation of a diet with up to 20% of white lupin had no adverse effects on the performance of broilers. Similar findings were reported by Lettner