Body composition, growth performance and enzyme activities of Labeo rohita fed different commercial fish feeds

We have evaluated the effects of different fish feeds on the body composition, growth, and enzyme activities of Labeo rohita (Rohu). In total, 240 fishes between the average weights of 24.77±2.15g were studied. The treatments were applied in a completely randomized design, with 4 treatments of 60 fishes each. Treatments consisted of four different fish feeds [Oryza (T1), AMG (T2), Aqua (T3), and Supreme (T4)]. Body composition, growth performance, and enzyme activities were evaluated. There was a significant variation in performance of fishes fed with different type of feed; as fishes having Oryza feed showed the highest weight gain, specific growth rate (SGR), and best feed conversion ratio (FCR) as compared to other groups that were considered to be significant (P ≤ 0.05). High net weight gain was obtained in T4 when compared with T2 and T3. FCR value of T4 was less than T1 but higher than T2, T3 and T2, which showed the lowest values. The specific growth rate was recorded as average in T4, but T2 led a high SGR than T3. Similarly, crude protein level and digestive enzymes activity was recorded significantly highest in fed with Oryza (T1) as compared to AMG (T2), Aqua (T3), and Supreme (T4). Water quality parameters were recorded significant in all treatments except pH and DO of treatment (T1), significantly different from other treatments. It was concluded that Rohu (Labeo rohita) could show a promising growth rate and protease enzyme activity when fed with the Oryza feed of 25% protein.

Development of production technology for extruded starter compound feedsfor juvenile fish

The article presents the results of developing recipes for domestic extruded starter compound feeds for zander, tilapia and Clary catfish. Technological modes of their production, as well as physical-chemical, mechanical and technological indicators of the developed compound feeds are established. The developed compound feeds are well-loose grains of dark and light brown colors, with sizes from 0,2 to 2,0 mm. Indicators of water resistance were at least 2,5 hours, crumbling no more than 1,5 %, swelling of granules 10-15 minutes, volume mass below 1000 kg/m3. The data obtained show that the developed feed meets the regulatory requirements for starting fish feeds. The introduction of the developed technology for the production of starter compound feeds at domestic enterprises of the feed industry will reduce the dependence of industrial fish farms on the import of compound feeds and thereby increase the profitability of the industry.

Rationale for the use of humats in aquaculture (a review)

Purpose. To prepare a justification for the use of sodium and potassium salts of humic and fulvic acids (humates) as substances with biologically active properties in fish feeds based on the analysis of sources of scientific and technical information and own experimental materials, Findings. A complex general characteristic of humic substances was provided, the mechanism of biologically active action of humates on living organisms was described. Examples of the use of humates in crop production, medicine, animal husbandry and aquaculture were given. The results of our own studies on the use of humates as a feed additive for valuable objects of aquaculture were presented. Prospects for the inclusion of micro-additives of sodium and potassium humates in the composition of fish feed in order to increase fish survival and digestibility of feed were outlined. Originality. To date, the introduction of humates into fish feed as micronutrients was experimental. The analysis of scientific sources and materials of own studies gave the basis for the conclusion about the need of complex detailed studying of mechanisms of effects of humates on fish. In particular, it is of interest to study the protective properties of humates from the accumulation of heavy metals in the body of fish for the use of micronutrients of these substances in fish feeds. Practical value. The use of humate feed additives in aquaculture will help to solve such urgent problems as the prevention of excessive losses of biological material of cultivated objects, reduction of feed costs, improvement of consumer characteristics of food products. Humates, as substances of natural origin with protective and immunomodulatory action, can become substitutes for some synthetic therapeutic and prophylactic drugs. Key words: aquaculture, humates, compound feed, feed additive, growth rate, survival, feed assimilation.

Modelling Kinetics of Extruded Fish Feeds in a Continuous Belt Dryer

Feed is the major inputs in aquaculture production which affects the development growth of aquaculture in the African continent. Extruded fish feeds are dried to desire moisture content to increase the shelf life. Conventional method of drying fish feeds had gained attention recently in Nigeria in order to reduce high cost of producing fish feeds. However, this method is still grossly underutilized. Extrude floating fish feed was dried using continuous belt dryer at drying air temperature from 60°C to 100°C at an interval of 10°C, velocity of air using for drying from 0.8 m s-1 to 1.0 m s-1 at an interval of 0.1 m s-1 using a constant linear belt speed of 50 m s-1. Various moisture contents gotten at different conditions were changed to ratio of the dried extrudates moisture so as to obtain curves of drying by plotting the ratio of moisture against time. The dried extrudates behaviour was determined by fixing the drying curves with five well known models. Model with high determination coefficient and low reduced chi-square, low standard error, low value of least square and low standard deviation error (SEE) was used as best model. Midilli et al model was found suitable in describing the behaviour of extruded fish feed during drying. The temperature of air used for drying was discovered to have a major influence on the drying kinetics of the extruded fish feeds based on the conditions of this experiment.

Modelling Kinetics of Extruded Fish Feeds in a Continuous Belt Dryer

Feed is the major inputs in aquaculture production which affects the development growth of aquaculture in the African continent. Extruded fish feeds are dried to desire moisture content to increase the shelf life. Conventional method of drying fish feeds had gained attention recently in Nigeria in order to reduce high cost of producing fish feeds. However, this method is still grossly underutilized. Extrude floating fish feed was dried using continuous belt dryer at drying air temperature from 60°C to 100°C at an interval of 10°C, velocity of air using for drying from 0.8 m s-1 to 1.0 m s-1 at an interval of 0.1 m s-1 using a constant linear belt speed of 50 m s-1. Various moisture contents gotten at different conditions were changed to ratio of the dried extrudates moisture so as to obtain curves of drying by plotting the ratio of moisture against time. The dried extrudates behaviour was determined by fixing the drying curves with five well known models. Model with high determination coefficient and low reduced chi-square, low standard error, low value of least square and low standard deviation error (SEE) was used as best model. Midilli et al model was found suitable in describing the behaviour of extruded fish feed during drying. The temperature of air used for drying was discovered to have a major influence on the drying kinetics of the extruded fish feeds based on the conditions of this experiment.

Application of Vermicompost Fertilizer in Aquaculture Nutrition: Review

Semi-intensive aquaculture using ponds is among the most common practices of fish production, whose output depends highly on the ponds’ natural primary productivity. With the increased sustainability and health concerns with artificial fish feeds and chemical fertilizers, organic manure has been credited as a cheap, safe and sustainable alternative source of aquaculture nutrition. Apart from supplying nutrients to the phytoplankton, organic manures supply food directly to zooplankton and fish, provide substrate for microbes and improve water and pond sediment quality. Vermicompost fertilizer (excrete of earthworms) has been recognized as a potential pond fertilizer because it has superior nutritional quality (of up to five times), contains microbes, and is in ready-for-uptake form. Besides, the vermicompost contains humic acid, which has antibiotic properties, and promotes fish gut health, stress management, and immune systems. Nonetheless, the application of vermicompost fertilizer in aquaculture is still not a common practice. Therefore, this study reviews the concept of vermiculture vis-à-vis pond fertilization and the various utilizations of the vermicompost in fish farming. This is to enable fish farmers to make an informed decision on identifying and selecting proper biofertilizer, which can increase yields and cut costs of production, thus maximizing profits and improving resource utilization.