Response of pigs fed a basal diet of water spinach (Ipomoea aquatica) to supplementation with oil or carbohydrate

Prak Kea

Royal University of Agriculture,
Faculty of Animal Science and Veterinary Medicine
Chamcar Daung, Cambodia
prakkea@yahoo.com / prakkea@hotmail.com

Abstract

Two experiments were conducted in the ecological farm of the University of Tropical Agriculture Foundation; Royal University of Agriculture, Kingdom of Cambodia. The first was a study of the influence of graded levels of palm oil on nutrient digestibility in young pigs fed diets based on water spinach and broken rice. The second was a study on the effect of the level of fish meal on growth and feed conversion of pigs fed a basal diet of water spinach supplemented with palm oil and broken rice.

Experiment 1.

Four crossbred castrate male piglets of 8-10 kg initial live weight were used in a 4 * 4 Latin square design to determine the effect of graded levels of palm oil (0, 5, 10 and 15%) on the intake, apparent nutrient digestibility and nitrogen retention in crossbred pigs fed diets based on broken rice and fresh, chopped water spinach supplemented with fish meal in a tropical environment (annual temperature ranged from 26 to 31^oC).

Daily DM intake as percentage of DM offered slightly decreased from 89.9 to 84.6%, and the apparent digestibilities of DM and ash significantly (P<0.05) decreased, as the proportion of palm oil increased in the diet. The palm oil level had no effect on digestibility of organic matter, crude fiber and N, nor on N retention.

It is concluded that fresh water spinach can provide up to 70% of the dietary protein for growing pigs, when it is supplemented with broken rice and up to 15% of palm oil.

Experiment 2.

The experiment was conducted at UTA (University of Tropical Agriculture, campus of the Royal University of Agriculture, Kingdom of Cambodia), with the aim of determining the effect of the level of fish meal on the performance of growing pigs fed a basal diet of fresh water spinach, broken rice and palm oil. Eight castrated males and 8 females (mean initial weights of 19.9 and 21.2, respectively ) were housed in individual pens and allocated to four dietary treatments according to a 4*2 factorial arrangement, the main effects being level of fish meal and sex. The dietary treatments were 0 [df0], 2 [df2], 4 [df4] and 6% [df6] of fish meal replacing water spinach (which comprised 50, 43, 36 and 29%, respectively of diet DM). Palm oil was constant at 10% of the diet DM while broken rice was 38, 43, 48 and 53% of DM, respectively. The experiment lasted from 3 July to 22 October 2002.

Daily dry matter feed intake was increased by supplementation with fish meal and the males consumed more than females. Growth rate was increased linearly (R² = 0.63), according to the level of fish meal, the improvement being more marked in the growing phase (53% improvement) than in the finishing stage (32% improvement). Feed conversion was improved by the fish meal in the growing phase but not in the finishing phase nor in the overall experimental period.

It is concluded that water spinach can provide a major part of the protein required for growing pigs fed diets based on broken rice, provided that it is supplemented with a source of methionine.

Key words: Pigs, digestibility, nitrogen balance, palm oil, water spinach, growth performance, feed conversion