Effects of dietary supplementation of crude extract product from guava leaves (Psidium guajava Linn.) on growth performance and carcass characteristics of fattening pigs

Abstract

The effects of crude extract product from guava leaves (Psidium guajava Linn.) on growth performance  and carcass characteristics of fattening pigs were studied. A total of 24 castrated male and 24 female  three-breed crossbred pigs (Large White × Landrace × Duroc) aged 28 days were divided into 6 groups with 4 replicates which consisted of two pigs each. The animals were randomly fed with dietary treatments as follows: control diet (supplemented with antibiotics), and diets supplemented with 10, 20, 30, 40 and 50 ppm crude extract product from guava leaves. Growth performances of pigs were evaluated in four periods of growth (4-9 weeks, 10-15 weeks, 16-20 weeks, and 21-24 weeks of age). The results showed that the supplementation of 10-50 ppm crude extract product from guava leaves significantly decreased average daily gain (P<0.01) and feed conversion ratio (P<0.05) of pigs compared with the subtherapeutic antibiotics group in the period of 4-9 weeks of age. On the contrary, the feed conversion ratio of pigs in the period of 10-15 weeks of age was significantly improved (P<0.05) by the supplementation of 20 ppm guava leaves crude extract product containing 0.05 ppm quercetin, whereas the average daily gain and feed intake were not significantly different among the groups. Responses of pigs in the period of 16-20 weeks of age agreed with those of 10-15 weeks of age, but no significant difference in growth performance was found. During the finishing period (21-24 weeks of age), the supplementation of 30 ppm guava leaves crude extract product containing 0.075 ppm quercetin provided better average daily gain (P<0.05) than subtherapeutic antibiotics supplementation, whereas the feed conversion ratio improved in tendency. Besides, the carcass characteristics in terms of back fat thickness, loin-eye area and lean percentage were evaluated at 24 weeks of age by real-time ultrasound. Although the significant effects of crude extract product from guava leaves were not found, the carcass characteristics improved in tendency, especially the back fat thickness. In conclusion, dietary supplementation of crude extract product from guava leaves at 20 ppm for the growing period (10-20 weeks of age) and 30 ppm for the finishing period (21-24 weeks of age) can be an alternative to antibiotics as growth promoter by improving the growth performance and carcass characteristics of pigs.