Effects of exogenous phytase in chickens fed diets with differently processed rapeseed expeller cakes

Abstract

The effects of phytase supplementation on the nutritional value, P availability and thyroid status of birds fed 4 differently processed rapeseed expeller cakes (RC) were determined. Two experiments were performed: a balance experiment on 10 groups of nine 3-week-old broilers and a growth experiment on 9 groups of one-day-old broiler females, 11 birds per group. In the balance experiment, a basal (B) and 4 test diets (B mixed with RC in a 6:4 proportion with DM) were fed; half of each diet was supplemented with 1000 U phytase/kg. In the growth experiment, the control diet without RC and isonitrogenous diets with RC supplemented or unsupplemented with 1000 U phytase/kg (RCP) were fed. The amount of RC was 100 or 150 g/kg in diets fed between days 1-21 and 22-42 of life, respectively. The levels of Ca and available P in RC diets were as in the control diet, while in RCP diets they were lowered by 7 and 12%, respectively.Phytase supplementation increased apparent protein digestibility and metabolizable energy values, while it did not affect P availability from RC. BWG was lower in some groups and FCR 5% worse (P<0.05) in all RC groups than in the control. The type of RC significantly affected feed intake, BWG, thyroid and kidney weight. Addition of phytase to RCP diets increased thyroid weight (P<0.01). Phytase addition did not fully compensate for lower Ca and P levels in RCP diets, as tibia ash content was reduced (P<0.05), but this had no effect on tibia weight and ultimate strength.

Nutritional value of rapeseed expeller cake for broilers: effect of dry extrusion

“…Protein solubility was determined in 0.5% KOH (NSI) and in borate. Protein dispersibility in water (PDI) and the available lysine content in cakes were measured, and the contents of crude fat, N total, N faecal and gross energy in cakes, diets and excreta were determined as described by Smulikowska et al (2006). Caecal contents were mixed with deionised water (1:1 w/w) and their pH was immediately measured using a digital pH-meter (WTW pH/340, Germany) against a pH standard WTW D-82362 Weilheim (model STP4) at room temperature.…”

“…The apparent protein and fat digestibility and metabolizable energy value of press cakes were calculated by the difference method as described by Smulikowska et al (2006). The results were subjected to one-way analysis of variance (ANOVA) generated by Statgraphics ® ver.…”

“…Rapeseed cakes seem to be more suitable components of broiler diets than solvent-extracted rapeseed meal as their metabolizable energy value is higher than that of rapeseed meal due to a higher residual oil content (Smulikowska et al, 1997(Smulikowska et al, , 2006. Moreover, the residual oil has a lower n-6/n-3 PUFA ratio than most of the fats used in broiler diets.…”

“…As a result, there is a potential for RC to derive additional value from partial disruption of fibre structures due to extrusion or the ammonia fibre explosion process (Newkirk and Classen, 2003). Apart from oil yield, additional treatments may affect myrosinase activity and glucosinolate toxicity, as well as protein digestibility and lysine availability in the final product (Smulikowska et al, 1997(Smulikowska et al, , 2006.…”

The effect of particle size of full-fat rapeseed and of multi-carbohydrase enzyme supplementation on nutrient digestibility and performance in broilers

“…Fine grinding possibly released part of the oil and increased the surface area, improving the rate of digestion by the birds' enzymes. Application of heat and mechanical treatments to FFRS proved to be beneficial in improving its nutritional value (Shen et al, 1983;Smulikowska et al, 2006). It is well known that grinding is used to disrupt the cell wall structure of feedstuffs to increase the exposure of nutrients to the digestive enzymes of animals, consequently, to improve bird performance.…”