Effect of rye level, fat source and enzyme supplementation on fat utilization, diet metabolizable energy, intestinal viscosity and performance of broiler chickens

Abstract

Two experiments were conducted on 272 young broiler cockerels to determine the effect of rye level, degree of saturation of added fat and supplementation with enzyme preparations containing xylanase and /3-glucanase on the nutritional value of rye-containing diets fortified with 8.5 (Experiment 1) or 6% (Experiment 2) fat.In Experiment 1, increasing the rye level (0, 15, 30 and 45%) in the diet containing 11.5% crude mixed fat significantly depressed (P «S 0.001) organic matter retention (OMR), protein (APD) and fat (AFD) apparent digestibility. The metabolizable energy value (AME N ) of the 45% rye diet was 8.5%lower than predicted because of this depression. Supplementation of diets with an enzyme preparation significantly improved OMR, AFD, AME N (P =£0.001) and APD (P^O.01) in ryecontaining diets. The AME N of the supplemented diet containing 45% rye was 1.7% higher than predicted.In Experiment 2, substitution of unsaturated (soya oil) with more saturated fats (lard or tallow, or soya oil and tallow 1:1) in the diet containing 30% rye, caused a significant decrease in AFD (P 0.001), OMR and APD (P < 0.05). The AME N of the tallow-containing diet was 1.28 MJ/kg DM lower than of the soya oil-containing diet. Cockerels fed the tallow-containing diet were lighter and used 13% more feed per gram of body weight gain (BWG). The degree of saturation of added fat did not affect the viscosity of intestinal digesta, but the viscosity of droppings was significantly higher in birds fed saturated fats.Enzyme supplementation significantly reduced (Pi?0.001) both intestinal and excreta viscosity, OMR, AFD and AME N . Cockerels fed enzyme-supplemented diets were on average 10% heavier and used 15% less feed per gram BWG. The greatest difference in the AME N value (1.65 MJ/kg DM) was noted between supplemented and unsupplemented tallow-containing diets.The results of these experiments suggest that enzyme supplementation is necessary in particular if broiler diets contain both a high level of rye and saturated animal fat.

Relationship between the stage of digestive tract development in chicks and the effect of viscosity reducing enzymes on fat digestion

“…It has been suggested that high digesta viscosity TABLE 2 Effect of rye level and enzyme supplementation on apparent fat digestibility (AFD), AME N and metabolizability of energy in 4-week old broiler chickens (after Smulikowska and Mieczkowska, 1996) Rye level, % Enzyme AFD AME N MJ/kg AME N /GE (Johnson, 1992;Annison, 1995). Viscous polysaccharides might also directly complex with digestive enzymes and reduce their activity (Ikeda and Kusano, 1983).…”

“…4 Effect of fat source and enzyme supplementation on AFD, AME N , metabolizability of energy, and viscosity of excreta and digesta (in cP) (after Smulikowska and Mieczkowska, 1996) Fat source Enzyme AFD AME, AME N /GE Viscosity, cP …”

Tolerance of broiler chickens to dietary rye soluble arabinoxylans

“…The results of these two experiments confirmed the major negative effect of SAX on dietary energy utilization and indicate the possibility of preventing this adverse effect by unsaturated fat supplementation. Earlier it has been shown that the performance of chickens fed a rye diet is markedly affected by the level of dietary fat (Antoniou et al, 1980) and that the fats rich in unsaturated fatty acids are better utilized by chickens than tallow or lard which are rich in saturated fatty acids (Antoniou et al, 1980;Choct et al, 1996;Smulikowska and Mieczkowska, 1996). Digestibility of unsaturated fatty acids was found to be very low (from 38 to 45%) in chickens fed a diet containing an equivalent of 4% soluble wheat pentosans (Choct et al, 1996).…”

Effect of changes in live body weight and feed conversion ratio as influenced by enzyme supplements on basic post-slaughter measurements of broiler chickens fed cereal-based diets

“…This effect was evident with diets fortified with fat, saturated fat in particular, and correlated with enhanced weight gains of birds (Smulikowska and Mieczkowska, 1996;Koreleski et al, 2000). On the other hand, several recent studies with chickens clearly showed an increase in carcass fat, as well as growth rate, with increasing dietary energy levels (Ya^in et al, 1998;Dublecz et al, 1999).…”