Rearing catfish Heteropneutes fossilis on feed supplemented by fermented leaf meal of Ipomoea aquatica

Replacement of fish meal by cost effective and sustainable plant resources in the formulation of feed for fish is a viable option to alleviate the current crisis in fish feed industries arising due to high cost and non-availability of fish meal. The present research was aimed to evaluate if fermented leaf meal of the aquatic plant Ipomoea aquatica could be used as a fish meal alternative in the formulation of feed for the catfish Heteropneustes fossilis.  Fresh green leaves of I. aquatica were sun dried and finely ground to make Ipomea leaf meal (ILM), which was then fermented for 12 days by the phytase producing bacteria Stenotrophomonas maltophilia strain KUAKSP1 (GenBank Accession No. KY790423) isolated from rumen of goat. Four iso-proteinous, iso-lipidous and iso-energetic feeds were formulated by replacing 0, 25, 50 and 75% of fish meal by the fermented Ipomoea leaf meal (FILM). Protein digestibility of the feeds was evaluated within 12 days in an indoor experiment in glass aquaria and growth performance of the fish was evaluated after 8 weeks rearing in outdoor cement tanks. H. fossilis grew better on FILM supplemented feed as compared to fish meal based control feed. Maximum apparent protein digestibility (APD) of the feed, maximum weight gain (WG) and specific growth rate (SGR) and minimum FCR of the fish were found in 50% replacement group. However, crude protein (CP) and crude lipid (CL) deposition in the muscle of the fish and activity of protease in the gut was higher in 25% replacement group. It is concluded that H. fossilis accepts and grows well on the plant based FILM supplemented feed. For better growth management of the fish, incorporation of FILM in the feed should be restricted to 25 to 50% of fish meal

Feeding and reproductive biology of Amblypharyngodon mola (Cyrpiniformes: Cyprinidae) from two floodplain lakes of India

Pattern of feeding and reproduction of Amblypharyngodon mola (Hamilton, 1822) was studied in two floodplain lakes of North 24 Parganas districts of West Bengal in India during 2011.  Results indicated that the fish exhibited a predominantly herbivorous diet with algae as the main content of gut. A long, thin walled, coiled gut and closely packed filamentous gill racker suited this feeding habit. Feeding intensity of the fish fluctuated throughout the year, males showing maximum intensity in June and females showing maximum intensity in February and November. Females outnumbered males (1.9:1) and were found as   highly fecund with a calculated fecundity factor of 1445 ova g-1 of body weight.  From the peak of gonado-somatic index and ova diameter it was revealed that A. mola apparently spawned only once during July in these floodplain lakes. It was concluded that improvement of ecosystem health of these two lakes were necessary to ensure spawning of the fish

Cypermethrin induced stress and changes in growth of freshwater fish Oreochromis niloticus

Abstract Bioassays were conducted with technical grade and commercial formulation of cypermethrin using freshwater fish Oreochromis niloticus as the test fish. The technical grade cypermethrin contained 92% active ingredient (a.i.) and the commercial formulation was an emulsified concentrate (EC) containing 10% a.i. (10% EC). Based on the actual concentration in water (2 h), the commercial formulation was found to be more acutely toxic to O. niloticus (96-h LC50 = 4.85 μg/L) than the technical grade cypermethrin (96-h LC50 = 9.74 μg/L). Exposure to sub-lethal concentrations (1.25, 2.5 μg/L) of commercial cypermethrin for 96 h produced stress on the fish, which was evident from the reduction of hepatic glycogen, reduction in the activities of alkaline phosphatase, acetylcholinesterase and catalase in liver and elevation of plasma glucose level and activities of hepatic acid phosphatase, aspartate aminotransferase and alanine aminotransferase. Exposure to these concentrations of cypermethrin for 14–28 days produced anaemia in fish. Long-term exposure (90 days) of the fish to these concentrations reduced the growth and deposition of protein and lipid in the body of fish as compared to control. It is concluded from this study that even minute concentration (1.25 μg/L) of cypermethrin (10% EC) in water can produce stress on fish. Long term exposure to such concentration of cypermethrin may also affect growth of the fish

Aquatic weed Ipomoea aquatica as feed ingredient for rearing Rohu, Labeo rohita (Hamilton)

Environment friendly management of the aquatic weed Ipomoea aquatica is possible through its utilization as ingredient in fish feed. In this study leaf meal of I. aquatica was fermented by phytase producing bacteria Stenotrophomonas maltophilia KUAKSP1 (GenBank Accession No. KY790423) isolated from the rumen of goat. Four experimental feed were formulated by replacing 0% (T1, Control), 25% (T2), 50% (T3) and 75% (T4) of fishmeal (FM) with the fermented Ipomoea leaf meal (FILM) as source of protein. Fingerlings of rohu, Labeo rohita were reared on these feed for eight weeks. The results showed that growth, daily retention of protein and nutrient deposition in L. rohita were significantly higher in FILM supplemented feed as compared to control. Best growth was obtained in 25% replacement of FM by the FILM supplemented feed (T2). α-amylase activity in T2 was significantly higher than control and other treatments (T3 and T4), while protease activity significantly increased in T3 and T4 as compared to T1 and T2. It was concluded that L. rohita could utilize limited amount of carbohydrate in the feed, there by sparing protein to render better growth of the fish. Keywords: Fermentation, Plant protein, Fishmeal, Phytase, Fish, Growt

Biomarkers of Type II Synthetic Pyrethroid Pesticides in Freshwater Fish

Type II synthetic pyrethroids contain an alpha-cyano group which renders them more neurotoxic than their noncyano type I counterparts. A wide array of biomarkers have been employed to delineate the toxic responses of freshwater fish to various type II synthetic pyrethroids. These include hematological, enzymatic, cytological, genetic, omic and other types of biomarkers. This review puts together the applications of different biomarkers in freshwater fish species in response to the toxicity of the major type II pyrethroid pesticides and assesses their present status, while speculating on the possible future directions