HARDENING EFFECT OF KAPOK MEAL ON FAT OF PIGS FED WITH DIET RICH IN LINOLEIC ACID

Abstract

Hardening effect of kapok meal on the storage fat of pigs given a ration containing 14% of soybean oil was evaluated. Twelve male Landrace pigs were used for the study, which were divided into 3 groups of varying diets. Group 1 was the control given 100% basal diet (Japanese Pig Progeny Testing Ration). Group 2 was given a mixture of 86% basal diet and 14% soybean oil. Group 3 was given a mixture of 82% basal diet, 14% soybean oil and 4% kapok meal, and the diet of Group 3 contained 0.054% cyclopropenoid fatty acids. Pigs were kept fed ad libitum since their age of 4 months for 7 weeks and were slaughtered at one time. Each carcass which was chilled for 24 hours was evaluated for firmness of fat. Samples were collected from the kidney leaf fat, and the inner and outer layers of back fat and were used for physicochemical analysis. No significant differences were observed in growth, feed consumption and carcass measurements except the firmness of body fat among the groups evaluated.
The dietary treatments exerted similar effects on the sampling sites of fat. Pigs given the control diet produced hard fat, whereas those Group 2 produced very soft fat and Group 3 produced soft fat. The results of hardness determination with Texturometer showed a similar tendency to the grossly examined firmness of the body fat. The fat samples of Groups 2 and 3 showed higher iodine number and refractive index and lower melting point and hardness than the counterparts of the control group. In general, the supplement of kapok meal increased the hardness of fat and elevated its melting point, but gave hardly any effects upon refractive index and iodine number of the fat. In the fatty acid composition of the storage fat of pigs, the supplemented soybean oil significantly increased the concentrations of linoleic acid, which amounted to as high as 32.0-36.5% in Groups 2 and 3. Supplementation of kapok meal reduced the ratio of stearic acid versus oleic acid.
From the above-mentioned results, it was suggested that supplementation of kapok meal certainly hardens body fat to some extent, but shows no appreciable effect upon selective accumulation of linoleic acid and that there would be a limit for improvement of soft fat with its addition under the condition of ample supplementation of linoleic acid.