This study was carried out to compare the performance of broilers fed diets containing only vegetable protein (VP) with birds that received an animal protein (AP) in their diets. Cobb 500 day-old male broiler chicks (n = 256) were randomly divided into four experimental groups. The two AP diets contained fish meal and soybean (SBF) and fish meal with canola (CMF); while the two VP diets contained predominantly soybean (SBM) or canola (CAN) meals. All diets were isoenergetic and isonitrogenous, and were pelleted, but amino acid levels were formulated on a total and not digestible basis. Feed intake up to 21 days was highest on the AP diets, and the lowest in the SBM treatment. Birds in the AP diet groups were significantly heavier at 21 days and 35 days than those on the VP diets. Up to 35 days, birds on AP diets had superior feed conversion ratio, while the CAN treatment was the poorest. Excreta moisture level was significantly higher in birds fed the VP diets than those on AP diets. Excreta pH and ammonia concentration were similar between treatments. Protein digestibility was higher in the AP than in the VP diets. Birds raised on VP diets had a significantly lower abdominal fat content than birds on the AP diets. Other meat characteristics measured in this experiment did not differ significantly. Bone development, in terms of breaking strength and latency-to-sit time, was significantly better on the AP diets than that of birds on the VP diets. The birds on the CMF diet had the longest tibia bone, while birds on SBM diet, the shortest. Total tibia ash content on the CMF diet was significantly increased, along with its iron and copper concentration, which were also significantly higher in birds on the same diet than the others. The responses of birds generally indicated that the AP diets were superior to the VP diets.________________________________________________________________________________

Maize cobs with grains were harvested at a relatively high moisture content (23%) from the field in northern New South Wales, Australia. The cobs were divided into four categories and dried in the sun or artificially in a forced draft oven at 80, 90 or 100 °C for 24 h. The samples were subjected to proximate and detailed nutrient analyses. In vitro nutrient digestibility and ultra structure of samples were also assessed. Proximate analysis of maize revealed that dry matter (DM, 980 g/kg) and ash (1.32 g/kg) content were highest in the 100 °C samples, but crude protein (98.4 g/kg), ether extract (45.0 g/kg) and phytate-P (1.8 g/kg) content were the highest in the sundried samples. Gross energy was little affected by heat treatment but the metabolizable energy value increased with rising temperature. The concentrations of most of the amino acids but not lysine were increased in samples dried at 80, 90 and 100 °C in comparison to sun drying. Total starch, resistant starch (RS) and amylose content were slightly increased by artificial drying while amylopectin was reduced under the same conditions. Starch content (691 g/kg) was highest at 80 °C while RS (363 g/kg) and amylose (304 g/k) were lowest in the same batch. The mineral concentration of samples decreased with increasing temperature except copper, which was slightly increased. The soluble non-starch polysaccharide (NSP) content was increased while the insoluble NSP decreased with increasing temperature. The morphological structure of maize observed under a scanning electron microscope showed some shrinkage of starch granules as a consequence of artificial drying temperature. In vitro digestibility of DM was improved as a result of artificial drying of high moisture maize but starch digestibility was reduced. It may be inferred that the nutritive value of maize grain varies with drying temperature and drying process. These differences may explain changes in nutritive value of the grain when fed to chickens.

No abstract

No abstract

The effect of feeding high-moisture maize grains dried in the sun or artificially in a forced draught oven at 80, 90 or 100 °C for 24 hours and supplemented with microbial enzymes (Avizyme 1502 and Phyzyme XP) on growth performance, visceral organs, tissue protein, enzyme activity and gut development was investigated in a broiler growth trial. Feed intake (FI) up to 21 days decreased as a results of oven drying of grains whereas supplementation with microbial enzymes increased FI compared to the non-enzyme diets (881.1 vs. 817.2 g/bird). The highest FI (900 g/bird) was found only in sun-dried grain diets. There was no effect of grain drying temperature or enzyme supplementation on FI when assessed at 7 days of age. Up to day 21 there was a reduction in live weight (LW) with increase in grain drying temperature while supplementation with enzymes significantly improved LW only on the diets containing sun-dried grains (731 g/bird) and grains dried at 90 °C (634 g/bird). Live weight was significantly higher in chickens on the enzyme supplemented diets than on diets without enzymes (638 vs. 547 g/bird). The feed conversion ratio (FCR) at this age was poorer with an increase in grain drying temperature but improved when the diets were supplemented with enzymes (1.48 vs. 1.62 g/g). There was an increase in the relative weight of the small intestine and liver with an increase in grain drying temperature at day 21 but there was no difference in the relative weight of these organs when the diets were supplemented with enzymes. Only the activities of the alkaline phosphatase at day 7 and maltase and sucrase at days 7 and 21 increased as a result of grain drying treatment but not by microbial enzyme supplementation. The ileal digestibility of gross energy, protein and starch was not significantly changed with an increase in grain drying temperature or by enzyme supplementation. The concentrations of ileal formic and acetic acids and caecal propionic and valeric acids were significantly increased by an increase in grain drying temperature but not affected by the microbial enzyme supplementation. The populations of lactic acid and lactobacilli bacteria in the ileal content were reduced on diets containing enzymes but were not affected by an increase in grain drying temperature. In the caecal content, the total anaerobic bacterial count was higher in birds on diets supplemented with microbial enzymes (8.1 vs. 7.8 log 10 cfu x/g digesta). The resident lactic acid bacteria population also increased as a result of an increase in grain drying temperature. From results of the current study, diets based on sun-dried maize or maize dried at 90 °C provided comparatively better gross response. It may be inferred that there was a positive response to addition of microbial enzymes. Overall, it may be assumed that, for broiler chickens, there is little or no difference in the nutritive value of sun-dried grain and grains artificially dried at 90 °C.