Comparative Study of Growth Performance of Heterobranchus Longifilis ( Valenciennes , 1840 ) , Reared With Two Organic Fertilizers in Earthen Ponds

The performance of Heterobranchus longifilis reared in earthen ponds fertilized with two organic fertilizers (meadow grasses and chicken droppings) was investigated. The study was carried out in 6 earthen ponds measuring 24.9 square meters each at Nigerian Institute for Oceanography and Marine Research (NIOMR) fish farm Ijoyi-Badore Lagos. Results obtained showed better food conversion ratio value in treatment 1 (1.28 ± 0. 11) fertilized with meadow grasses and chicken droppings in combination with commercial extruded feed than in treatment 2 (1.72 ± 0.32) fertilized with only chicken droppings in combination with commercial extruded feed. The total weight gain were 665.39 ± 22.05Kg and 623.93 ±40.64kg respectively for treatment 1 and 2 while the daily growth rate was 4.01 ± 0.13g and 3.76 ± 0.24g for treatment 1 and 2 respectively. H. longifilis in treatment 1 performed better than treatment 2 probably due to the efficiency of the organic fertilizers in treatment 1 than treatment 2. Fertilizer used in treatment 1 could be used in fish ponds to reduce cost of pond fish production.


Introduction
In Nigeria, fish culture is one of the predominant aquaculture activities and most of the culture is land based.Heterobranchus longifilis (Plate 1) belongs to the catfish family clariidae that has gained widespread recognition as promising specie in aquaculture production (Lennient, et al. [16]).H. longifilis is an economically important food fish cultured primarily in fresh water ponds in tropical countries (Babalola and Aputa, [6] and Akinwole and Faturoti, [3]).This specie exhibits many qualities which makes it suitable for commercial culture.These include such as hardiness, rapid growth, high disease resistance, high yield potential, high fecundity, air breathing characteristics and good market potentials (Ayinla, et al. [5]).The traditional and extensive fish cultures is dependent on the natural pond productivity, while the semi-intensive and intensive fish culture system developed than extensive by using of various inputs such as manures, fertilizers and supplementary feed (Charabarty et al. [8]).Moreover, Charabarty, et al. [8] reported that the in freshwater fish ponds, total primary fish production, mainly depend upon the availability of nutrients, nutrient recycling and primary nutrients in the form of organic and inorganic fertilization and artificial feed .Attention has been paid to enhance the natural productivity of the pond through the application of different types and dosages of manures and fertilizers, fish species to be stocked and their compatibility (Britz,et al. [21]).Fish production can be increased by feeding and pond fertilization.Optimum fertilization rate is the amount of organic matter that should be cost effective and can be utilized in a pond ecosystem without having harmful effect on water quality as well as on fish growth (Abass, et al. [1]).To improve the productive efficiency of fish ponds and to have a maximum yield from the limited resources of fresh water bodies, it is necessary to fertilize the fish ponds with balanced food in sufficient quantities.Pond fertilization using both organic manure and inorganic fertilizers is the latest management protocol to enhance the biological productivity of treated waters (Dhawan and Kaur, [10]; Bhakta, et al. [7]).The basic principle behind the fertilization of a fish pond with suitable manure is to actually increase the production of beneficial phytoplanktons, the key component of aquatic food chain which is responsible for increasing the amount of harvestable fish.It is estimated that pond fertilization can enhance the fish harvest of the given water body up to 2.8 times of an unfertilized pond (Hayat,et al. [14]; Godara, et al. [13]).
The types of fertilizers used are organic and inorganic fertilizer which boost the nutrient content of ponds and promote the yield of natural food required by the aquatic organisms, especially fish.Conte, [11] stated that organic fertilizers like hay, straw and manure are among the earliest sources of fertilizers and are commonly used throughout the world to initiate alga blooms in fish pond and is important for pond productivity.The aim of this work is to carry out a comparative analysis of two organic compositions and evaluate fish growth performance.
The mortality rate (%), did not give significant difference within the Treatments due to the wide gap in their values.
The value for the nutrient utilization parameters are presented in Table 2 while protein intake (g) values obtained were 355.865 and 472.659 g for Treatments 1 and 2 respectively.These values are higher than the values obtained by Adewolu, et al. [2] for C. gariepinus, 81.07g, H. longifilis 59.33 g and their hybrid, 98.99 g.The protein efficiency ratio (PER) (g) obtained in treatment 2 was 1.321 g which was lower than the values obtained by Adewolu et al., (2008) for C. gariepinus (1.59) and Hybrid (1.63) but the value obtained for treatment 1 was higher than those of Adewolu, et al. [2] for H. longifilis (1.87).The apparent net protein utilization (ANPU) (%) obtained were 0.953 and 0.791% in treatments 1 and 2 respectively (Table 2).

Conclusion
The physico-chemical parameters obtained in this study were within tolerance range the performance of H. longifilis reared in the two treatments were, very good since the result showed rapid growth rate and efficient feed utilization.Data obtained from the study indicated that meadow grasses can be effective in pond culture of H. longifilis leading to lower production cost.

Table 1 :
Mean Values of Some Growth Parameters of H. Longifilis

Table 2 :
Protein utilization of H. Longifilis