The effect of replacement of soyabean meal with blood meal on the growth of mudfish Clarias anguillaris (L) fingerlings

Blood meal and full fat soyabean meal were mixed in different proportions to give 0%, 10%, 25%, 50%, 75%, 90% and 100% meal in the protein fraction of the diet and fed to Claria anguillaris fingerlings in floating hapas. The growth performance of the fingerlings were monitored for 84 days. At the end of the experiment the mean weight of the fingerlings increased in the level of blood meal up to 50% blood meal in the diet after which there was a decline in the mean weight of the fish. This same level of blood meal gave the best specific growth rate, feed conversion efficiency and protein efficiency ratio. Thus the nutritive value of blood meal was enhanced by the addition of an equal level of full fat soyabean meal in the diet

Using eye lens diameter as age indicator of young Lithognathus mormyrus and Diplodus vulgaris

Eye lens diameter was analyzed in two sparid fish species, Lithognathus mormyrus and Diplodus vulgaris, in order to determine the possibility of using these data for age determination. The results showed that the technique could be adopted for determining the age of the two species when the specimens are very young. The method is especially useful for age determination when otolith or scale rings are not visible or when false rings may give erroneous readings.

Effectiveness of a Rigid Grate for Excluding Pacific Halibut, Hippoglossus stenolepis, From Groundfish Trawl Catches

A rigid grate was installed in a groundfish trawl to test its effectiveness in excluding Pacific halibut, Hippoglossus stenolepis, from commercial flatfish catches in the Gulf of Alaska. The grate was located ahead of the trawl codend to direct halibut toward an escape opening while allowing target species to pass through toward the codend. In an experimental fishery, the escape rate of halibut was estimated at 94%, while 72% of the Dover sole, Microstomas pacificus, 67% of the rex sole, Glyptocephalus zachirus, and 79% of the flathead sole, Hippoglossoides elassodon, were retained.

Partial replacement of fishmeal protein by soybean meal protein in the diet of mrigal, Cirrhinus cirrhosus (Ham.) fry

To find out a suitable balance diet for Cirrhinus. cirrhosus fry substituting fish meal protein by full-fat soybean meal protein as dietary protein source for C. cirrhosus fry (1.29g) was studied in 12 aquaria for 60 days. The fishes were fed with four iso-nitrogenous (30% protein) and iso-caloric experimental diets viz. diet 1 (100% fish meal protein), diet 2 (75% fishmeal protein and 25% soybean meal protein), diet 3 (50% fishmeal protein and 50% soybean meal protein) and diet 4 (25% fish meal protein and 75% soybean meal protein). Among the diets the best growth, FCR and PER were obtained with diet 3 fed fishes and no significant difference (p<0.05) was observed between diet 1 and 2 and diet 4 offered the worst performance. Therefore, considering fish growth, FCR and PER, it can be suggested that fish meal protein might be replaced 50% by soybean meal protein in the diet of C. cirrhosus fry for better growth.

Electrophoretic characteristics of oil sardine (Sardinella longiceps) and mackerel (Rastrelliger kanagurta) eye lens proteins

Electrophoresis of eye lens proteins of oil sardine and mackerel showed separation of proteins into three and four components, indicating the heterogeneous nature of the population.

Use of eye lens diameter and weight as an age indicator in the carangid fish, Decapterus russelli (Pisces: Carangidae) from Gulf of Oman: preliminary observation

Specimens of Decapterus russelli have been collected from Lema, north of the Gulf of Oman. The ocular lens diameter and weight were tested as an additional age indicator to those already in use. The results showed that this technique could be adopted for determining the age of the species Decapterus russelli when the specimens are in the second year of age in case of eye lens diameter. On the other hand, eye lens weight failed to separate between the four age groups observed. The method is especially useful for age determination when otolith or scale ring are not visible or when false rings give erroneous reading.

Effect of replacement of fish meal with soybean meal plus supplementary enzymes on growth performance, survival rate and apparent digestibility of rainbow trout (Oncorhynchus mykiss)

This study was carried out to measure the effects of a supplementary multi enzyme on growth performance , survival rate and apparent protein digestibility of rainbow trout fed some diets containing different amounts of soy bean meal. Five exprimental diets with replacement of 25, 50, 75 and 100 percent of fish meal protein by soy bean meal protein were made and 0, 500 and 1000 ppm dosages of supplementary multi enzyme had used in each of them. By the means a diet with fish meal as the only source of protein has used as the control. So this study had 13 treatments. The trouts in 89.40±4.01 gr mean weight were stocked in 39 experimental fiberglass tanks in abundance of 30 fish per any tank. These specimens fed experimental diets for 8 weeks and ten of them in each tank fed same diets which added Cr2O3 to them for one more week to measure the apparent protein digestibility in them. The results shown that supplementary multi enzyme (Avizyme) which contains Protease , Amylase and Xylanase , caused increases in growth performance , survival rate and apparent protein digestibility in trouts which fed soybean meal. Also this study shown that using 1000 ppm of Avizyme in diets which containing soybean meal had the best results and the diet which contained 39 % soybean meal with this amount of enzymes, had no significant differences by the control in any of the studied factors.