The effects of dietary fat supplementation on performance, fatty acid (FA) composition of tissues and antioxidant defence system of broilers were studied. Male broilers were placed in 20 floor pens (60 broilers per pen). The broilers were fed by diets with added different energy sources: lard (L); sunflower oil (SFO); soybean oil (SBO); and linseed oil (LSO). The treatments did not modify significantly growth performance and feed intake of the broilers. There was no effect of dietary FA pattern on reduced glutathione level and glutathione peroxidase activity of plasma, erythrocyte and liver samples. However, higher PUFA content of the diet resulted in a significant increase in malondialdehyde level of erythrocytes and liver. The broilers fed LSO diet more effectively maintained their antioxidant status with enhanced plasma radical scavenger capacity. FA composition in tissues reflected the FA pattern of the diets, although proportion of FAs with four or more double bonds was metabolic specific. LSO diet increased the level of C18:3, C20:5 and C22:6 in tissue lipids in relation to L, SFO and SBO diets. Significantly increased plasma radical scavenging capacity in concert with the enhanced C20:5 and C22:6 proportion in liver and muscle during LSO feeding indicate metabolic changes to counteract the oxidative injury. This may be related to the compounds produced after different biochemical pathways of n-6 and n-3 FAs.

The effects of different heat treatments were studied on chemical composition, protein degradability, amino acid composition, trypsin inhibition and urease activity. Three lactating Holstein cows fitted with rumen cannulae were used. Fullfat soybean was prepared employing different forms of heat treatment: dry-extrusion at 150 degrees C for 25 s (treatment I); wet-extrusion at 95 degrees C for 30 min (treatment II); toasted soybean at 105 degrees C for 30 min (treatment III) extracted soybean meal (treatment IV); and untreated soybean (treatment V). The incubation times were 0, 2, 4, 8, 16, 24 and 48 h. Samples of raw and heat-treated soybean before incubation and the undegraded fraction after 4 and 16 h of incubation were analyzed for amino acids. The results showed that heat treatments did not modify chemical composition, but significantly reduced the content of trypsin inhibition and urease activity, as well as decreased protein degradability. The dry extrusion technique was comparatively the most effective. Amino acid content was not significantly influenced by different techniques, but the quantity of amino acids escaping degradation in the rumen increased.

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Scientific feeding experiments with hybrid pigs of the type Hungahib in the fattening period between 30 and 100 kg were carried out with one repetition as part of a joint international experiment. Feed, nutrient and energy expenditure were tested on 3 levels of energy supply (100 : 85 : 70%) and 3 levels of protein supply (18 : 16 : 14%) in the fattening period between 30 and 60 kg and 16 : 14 : 12% in the fattening period between 60 and 100 kg). In addition to this, parallel metabolism experiments were carried out to determine the digestibility and the N-balance of the feed mixtures used. The cost of feeding was also taken into consideration. The best results with regard to the fattening performance and the minimising of feed cost were achieved with the following ration type: (Table: see text). The fattening performance with this ration type was 712 g average daily live weight gain in the range between 30 and 60 kg live weight in the 1st fattening experiment and 601 g in the 2nd fattening experiment. A classification of the expenditure values has been attempted in the 10th contribution to this series of publications dealing with the total results of the joint international experiment.

The objective of the experiment was to examine the effect of phytase addition on absorption and apparent digestibility of P when a maize-soyabean meal-based diet was supplemented by different levels of inorganic phosphate. An isotope ( 32 P) metabolic experiment was carried out on crossbred barrows (initial BW of 15-18 kg). The dietary treatments were arranged in a 2 × 2 factorial design with two levels of total P (A:0.67 and L:0.59%) having different levels of P bioavailability (A:0.36 and L: 0.28%), and two levels of microbial phytase (0 and 500 FTU/kg of diet). In phase 1 the pigs in groups 1/a and 1/b were fed diets with two levels of P (A and L) without phytase. In phase 2, these pigs were fed diets of A and L with enzyme supplementation (groups 2/a and 2/b). The apparent digestibility of nutrients was unaffected by phytase. Pigs fed diet L had decreased organic matter-and ether extract digestibility. In group 1/a the piglets digested 52.3% of the total P and a similar value was found in group 1/b. As the result of phytase supplementation, the digestibility of the total P increased by 7% in group 2/a and 23% in group 2/b. The digestibility of P originating from inorganic P supplementation (monocalcium phosphate) decreased by 11 and 4% in groups 2/a and 2/b, respectively. The apparent digestibility of phytate P was not affected in the animals fed the diet without enzyme supplementation (1/a and 1/b). However, phytase enhanced the apparent digestibility of phytate P from 31.6 to 43.9% and from 35.8 to 54.5% in pigs fed diet 2/a and 2/b, respectively. These results show that faecal excretion of inorganic P increases and absorption of phytate-P improves by the action of phytase. In summary, the amount of inorganic P supplementation can be decreased and it is environmentally advantageous to replace inorganic P with microbial phytase.