The effect of date fibre supplemented with an exogenous enzyme on the performance and meat quality of broiler chickens.

1. Two experiments were conducted to evaluate the use of date fibre as a partial replacement of maize as a source of energy for growing broiler chicken. In experiment 1, date fibre was given alone to determine apparent metabolisable energy (AME) and apparent ileal digestibility of amino acids and crude fibre. 2. Date fibre had lower AME content (8.7 vs 13.6 MJ/kg) and apparent ileal digestibility coefficients for dry matter (0.35 vs 0.83), crude fibre (0.20 vs 0.54) and amino acids. 3. Based on the results of experiment 1, a growth study was conducted to test the effect of exogenous enzymes on the nutritive value of date fibre (experiment 2). 4. Three date fibre contents (5, 10 and 15%) with and without enzyme supplementation were evaluated. Daily feed intake, body weight gain and feed conversion ratio were measured. At the end of experiment 2, 160 birds were randomly selected and slaughtered to evaluate carcase and meat quality traits as well as measuring ileal viscosity. 5. Substitution of maize by 10 and 15% date fibre significantly depressed AME. Enzyme supplementation did not improve crude fibre digestibility. The inclusion of date fibre in the diets except at 5% decreased average daily gains, feed intake and feed conversion ratio. 6. Addition of date fibre caused a significant increase in the weights of total digestive tract, pancreas and caecum. Addition of date fibre or the exogenous enzyme had no significant effect on carcase or meat quality characteristics. 7. Date fibre increased ileal digesta viscosity compared to the control. Addition of the exogenous enzyme decreased the viscosity of the basal diets but had no effect on the date fibre diets.8. This study indicated that date fibre can be included at levels of 5% in broiler diets without affecting performance.

Effect of dietary lipase enzyme on gut morphology, gastric motility, and long-term performance of broiler chicks.

Three experiments were conducted to test a previously described anorexic effect of graded dietary supplements of Pancreatic lipase enzyme on gut structure, gastric motility, and long-term performance of broiler chicks. In Experiment 1, dietary Pancreatic enzyme was used at graded levels of 0, 0.214, 0.429, 0.643, 0.857, and 1.071% to test the effect of this enzyme on gut structure, whereas Experiment 2 was designed to test its effect at 0, 0.268, 0.536, 0.804, 1.071, and 1.339% on gastric motility. The histological examination of the small intestine and a cineradiographic study of birds fed diets supplemented with lipase enzyme failed to detect any difference in gut structure, and there was no apparent adverse effect on gastric motility. Experiment 3 was conducted to test the effect of graded supplements of Pancreatic enzyme on performance of 300 male broiler chicks raised for 6 wk to determine whether the enzyme had any long-term effect on performance characteristics, especially feed intake. Only starter diets (0 to 21 d) were supplemented with 0, 0.375, 0.750, or 1.125% enzyme, and each diet was represented by three replicate pens of 25 male chicks each. Subsequent diets did not contain any enzyme. During the first 3 wk, increased dietary concentration of lipase enzyme caused a linear reduction of feed intake and body weight gain (P < 0.01). At 21 d the percentage weight of the liver was significantly greater with 1.125% enzyme (P < 0.01). However, added enzyme had no effect on 21 to 42 d or 1 to 42 d growth or feed intake (P > 0.05) or on the size of any internal organs examined at 42 d. Pancreatic enzyme has previously been shown to improve fat digestion and increase diet AMEn for young chicks fed animal-vegetable blended fats. These positive effects, however, are associated with marked anorexia, and from the present study, it seems that this effect was not related to physical changes in gut histology or in prolonged digesta transit time.

Evaluation of dietary supplements of lipase, detergent, and crude porcine pancreas on fat utilization by young broiler chicks.

The purpose of Experiment 1 was to improve the digestibility of fat through the use of supplemental lipase enzymes. A 2 x 3 factorial arrangement of treatments involving two levels of animal-vegetable blend fat (AV) (4 and 8%) and three enzyme treatments, namely none; Pancreatic, 0.714%; and Pancreatin, 0.714%, were randomly allocated within a battery brooder. There was an increase in diet ME and apparent fat digestibility when Pancreatic and Pancreatin enzymes were used (P < 0.01). However, both enzymes caused lower feed intake and lower BW gain (P < 0.01). In Experiment 2, Pancreatic enzyme was used at graded levels of 0, 0.214, 0.429, 0.643, 0.857, and 1.071%, involving 4% dietary AV fat. The ME values were greater as the enzyme level increased (P < 0.01). However, as found in Experiment 1 lower feed intake and BW gain were observed with all enzyme levels compared with the control group. There was a linear effect on feed intake and BW gain (P < 0.01) and a quadratic effect on apparent fat digestibility (P < 0.05) and feed utilization (P < 0.01). Experiment 3 was designed to test the effect of Pancreatic enzyme at 0 or 1.339% in combination with two levels of detergent, namely 0 and 10% (with 4% added AV). The detergent used consisted of a mixture of 95% Span 60 and 5% Tween 60. In general, there was no significant effect of detergent (P > 0.05). Experiment 4 was conducted to test the effect of supplementation of graded levels of ground crude porcine pancreas at 0, 0.321, 0.535, 0.750, 0.964, 1.178, or 1.392% of the diet on performance of male broiler chicks to confirm the anorexic effect caused by supplementing with Pancreatic enzyme. In general, there was no significant effect of feeding crude porcine pancreas on the performance of male broiler chicks (P > 0.05). In these studies, lipase enzymes improved fat digestion, although it is suspected that associated reduced feed intake may be associated with contaminants such as cholecystokinin hormone.