INFLUENCE OF SQUID LIVER MEAL IN MATURATION DIET ON GONADOSOMATIC INDEX AND GONADAL AMINO ACID CONTENT OF GOLDEN SPOTTED RABBITFISH, Siganus guttatus

Abstract

A four months feeding trial was conducted to evaluate the effects of two maturation diets containing either fishmeal (FM) or squid liver meal (SLM) as the major protein source on growth, gonadosomatic index and gonadal bio-chemical profiles of golden spotted rabbitfish, Siganus guttatus. The two tested diets were formulated to be iso-nitrogenous (40%) and iso-lipidic (14%) and supplemented with several micronutrients specifically for gonadal development. The initial weight of golden spotted rabbitfish used were 352.6 ± 45.0 g and stocked into four of 2 m x 2 m x 2.5 m net cages with 25 fish per cage. The test diets were fed to the stocks twice a day. After four months feeding, the weight gains (WG) of broodstock fed the two diets were nearly similar in which FM had WG of 40.1 ± 2.2% and 42.8 ± 2.0% for SLM. The GSI of male fed SLM diet was similar to that of fed with FM. However, the GSI of female fed FM was 5.6 ± 0.1% significantly lower (P<0.05) than SLM which was 11.4 ± 0.5%. Furthermore, total amino acid (TAA) in spermatocyte was significantly (P<0.05) influenced by dietary SLM indicated by its higher TAA (62.4%) compared to TAA content of FM group (46.1%). Similarly, the TAA content in oocyte was significantly (P<0.05) improved when fed SLM. The dietary SLM did not affect the TAA content in the fillet of rabbitfish demonstrated by the similarity of the fillet TAA content in the two groups which was 55.6% for FM and 54.1% for SLM. Dietary SLM enhanced GSI of female broodstocks and profile of amino acid in the gonad of golden spotted rabbitfish, Siganus guttatus.

Growth performances and gonadal development of golden rabbitfish, Siganus guttatus fed with two types of floating diets in sea cages

“…The findings also demonstrated that application of floating diets containing CP content closely to requirement level for grow-out (33%) can also stimulate the gonadal development of rabbitifish up to the ealier stage of maturation. The GSI of oocyte obtained in this present study was lower (9%) compared when golden rabbitfish fed with maturation diet contained 40% CP [24]. This indicated that protein requirement for maturation stage of golden rabbitfish is higher than for grow-out.…”

“…The lower growth rate of fish fed floating feed containing 26% CP (FD1) obviously demonstrated that the protein level cannot support the proper growth rate of golden rabbitfish even at the bigger size. The mean final weight of 371.77±8.4 g in fish fed the FD2 diet may approach the size of maturation stage of golden rabbitfish [24].…”

“…This indicated that protein requirement for maturation stage of golden rabbitfish is higher than for grow-out. High amount of protein in both oocyte and spermatid which were 68.5 and 76.7%, respectively [24], also implied that reproduction stage required higher protein requirement. Moreover, type of protein sources and other ingredient used for formulating maturation diet significantly affected the reproductive performances of fish [36] including golden rabbitfish [24].…”