Manuel A. Laron

Reproductive performance and growth of Nile tilapia (Oreochromis niloticus) broodstock fed diets containing Leucaena leucocephala leaf meal

The effects of dietary leucaena leaf meal on reproductive performance and growth of Nile tilapia were determined. In the preliminary trial, sexually mature Nile tilapia were fed with a control diet or a test diet which had leucaena leaf meal as the only protein source for 24 weeks. Fish fed with the leucaena diet lost some weight and had significantly low (P 0.05). However, growth of males fed with the 80% leucaena diet was remarkably low. Fry production was highest for those fed with the control diet and the 20% leucaena diet. Fry production decreased slightly in fish fed with the 40% leucaena diet and was significantly low (P<0.05) for those fed with the 80% leucaena diet. The low fry production was preceded by a decrease in body weight of the female fish. However, the gonadosomatic indices of the females and the males were not markedly affected by the diets. On the basis of both fry production and growth, leucaena leaf meal should not exceed 40% of the diet of Nile tilapia broodstock.

The effects of artificial diets on fry production and growth of Oreochromis niloticus breeders

Abstract Tilapia breeders were fed with pelleted supplemental diets containing 20 or 40% crude protein at a daily feeding rate of 1% of fish biomass for 24 weeks in cages and tanks. Breeders were weighed and fry were collected at 3-week intervals. The 40% protein diet consistently gave the highest fry production and growth of breeders. The 20% protein diet gave variable results; fry production and growth were comparable to those of breeders fed with the 40% protein diet in some trials but significantly low in others. Breeders without supplemental feeding invariably had the least number of fry and the lowest body weights.

Growth and reproductive performance of bighead carp (Aristichthys nobilis) reared with or without feeding in floating cages

Abstract Bighead carp (10.5 months old) stocked in cages in Laguna de Bay were assigned the following feeding treatments: 1. 40% protein diet, 2. 20% protein diet, and 3. no artificial diet (control), to determine the effects of feeding on growth and reproduction. The fish were fed for 15 months. Growth was monitored for the first 9 months and fish were induced to spawn in the succeeding months. Both weight gain and increase in total length did not differ significantly ( P > 0.05) among treatments. Results of the induced spawning showed that fish fed the 40%-protein diet had the highest mean total weight of eggs/female, total number of eggs/spawning, and number of eggs/kg body weight. Fish fed the 20%-protein diet had intermediate values while the control fish had the lowest values for the same parameters. However, mean fertilization rates (54–58%) and hatching rates (61–78%) were not significantly different ( P > 0.05) among treatments. The mean number of 3-day old fry of fish fed the 20%-protein diet (48 085) was lower than that of fish fed the 40%-protein diet (86 806). The control fish gave a significantly low ( P

Larval and early juvenile development of silver therapon, Leiopotherapon plumbeus (Actinopterygii: Perciformes: Terapontidae), reared in mesocosms

This work was supported by SEAFDEC Aquaculture Department under the Study code: Nr-04- F2010B. We express our gratitude to Miss Julie Andrea P. Anano, Mr Nemencio B. Olorvida and the student interns from the Polytechnic University of the Philippines (Santa Mesa, Manila) for their assistance during the study.