1. Introduction

Integrated livestock-fish farming is a practice which links together two normally separate farming systems, whereby the livestock and fish become sub-systems of a whole farming system. Integrated farming is based on the concept that “there is no waste”, and “waste is only a misplaced resource which can become a valuable material for another product” [1, 2]. Fish production figures reported in various published literature ranged from 1.5 ton ha^-1 yr^-1 to 18 ton.ha^-1 yr^-1. The higher fish production is attainable through intensive management inputs, involving high stocking densities of complementary-feeding fish species, addition of energy-rich supplementary feed to a significant component of natural feed, and aeration of fish pond water. The rising cost of high protein fish feed and inorganic fertilizer, as well as the general concern for energy conservation, have brought about increased interest in the utilization of animal manures in aquaculture and in the traditional systems which integrate animal husbandry with aquaculture [3, 4]. The integration of livestock with fisheries aquaculture has received considerable attention lately with emphasis on the incorporation of animal manures as fertilizer and nutrient for promotion of natural feed in fish ponds [5, 6]. The rationale behind integrating fish with livestock is the large amount of nutrients (N-P-K) present in the animal feed being recovered in the manure, with possible proportions of 72–79% nitrogen, 61–87% phosphorus, and 82–92% potassium. These act as fertilisers in fish ponds to produce plankton which comprise high-protein natural food for certain species of fish. Recent experiments have demonstrated that considerable fish production can be obtained when animal manures are properly applied to fish polyculture systems [7]. Polyculture of carps, channel catfish and largemouth bass with manure wastes from 66 pigs per ha as the only source of nutrients yielded 4 ton ha^-1 yr^-1 [8]. Supplementary addition of chicken droppings under conditions of intensive fish culture increased fish yield by 21% and decreased the feed conversion rate by 0.4 units [9].

Integrated animal-fish farming could be an appropriate means for increasing returns from a limited land area and reducing risk by diversifying crops [10, 11, 12]. However, before mounting a development effort to popularize animal-fish farming, available production methods need to be adapted with the prevailing local climate and locally marketable fish species, and the economic viability of the system be ascertained. The present study is focused to evaluate fish-livestock polyculture systems that would provide the highest economic return, giving manure as the only nutrient source and clarify the economics of the developed production system. The goal of these research studies is the well-being of farmers that adopt improved technologies, and the ultimate test of research value is if farmers themselves demonstrate the economic benefit by incorporating new technologies to their farming systems. Therefore, economic analysis of the cost and benefits to the farmers of the various integrated fish-pig and fish-poultry farming systems will provide insight into the value and benefits of these technologies to farmers.

2. Materials and Methods

Experimental site and pond facilities

Six rain-fed, rectangular farmers’ fish ponds (each approximately 250 m², 1.6 m deep), situated in NAIP cluster area of East Kalcho village (Lat. 22^o24’05.0”N, Long. 92^o57’23.0”E, 177 m asl) in Saiha district of Mizoram, North-East India were selected to carry out experiment from August, 2010 to July, 2011.

Experimental design and feeding

The experiment was carried out with two treatments, each with three replications. The first treatment consisted of directly integrating fish with one piglet (Hampshire variety), and the second treatment consisted of directly integrating fish with poultry birds (Broilers). The pig and poultry units were maintained with commercial feed and local available materials. However, no commercial fish feed was applied in each of the treatments, but locally available vegetative feeds were being given. All the treatments were stocked with fish component consisting of fingerlings, viz. Rohu (Labeo rohita), Silver carp (Hypophthalmichthys molitrix) and Grass carp (Ctenopharyngodon idella) in the ratio of 2:2:1 respectively with a stocking density of 10000 fingerlings ha^-1.

Fish pond renovation

Each of the experimental ponds was applied 2 kg of commercially available bleaching powder as fish toxicant to remove weed fishes, insects and unwanted organisms. Since total dewatering is not possible, so depending on the feasibility some percentage of pond water was pumped out and the same was refilled with new water. About 10 kg of quick lime is applied to maintain the requisite water pH for fish farming.

Construction of pig sty and poultry house

The pig sties were constructed on the pond embankments and the pig excreta were washed away directly to the fish pond. A diversion channel was provided to divert the excreta away from the pond in case if algal bloom or any other abnormality develops. The poultry houses were also constructed on the pond embankment, and below the cage some pots were placed to collect the poultry droppings which were then applied to the fish ponds.

Rearing of pig and poultry

The piglets were reared intensively that they were not allowed to go out of the pig sties. The pigs were fed balanced feed (pig mash) @ 1.4-1.5 kg per pig day^-1, divided into 3 equal instalments per day. Along with these balanced feed, they were also fed green grass and locally available vegetative materials, kitchen waste, spoiled vegetables, etc. These pigs were ready for slaughter in 6 months, hence 2 lots of pig was being raised in a year. In the fish-poultry farming, the poultry birds were also intensively raised, not allowed to go outside of their houses. Poultry birds were fed with balanced poultry feed @ 70-80 gm per bird day^-1 in about 4-5 times a day upto the age of 6-7 weeks of birds. In this system, 6 lots of poultry birds were raised in a year.

Fish stocking and harvesting management

In all the experimental treatment ponds, fingerlings of Rohu, Silver carp and Grass carp with initial weight of 4-6 gm were procured from a local fry trader. These fingerlings were stocked 15-20 days after bringing the piglets and the poultry birds to their houses. Fingerlings stocking was done in the morning hours through proper conditioning to adjust with the new environment. The treatment ponds were applied lime (about 2 kg per month) for the remaining 11 months. Pig excreta and poultry droppings acts as the feed for the fishes under experiment, however locally available vegetative materials like, grass, maize leaves, banana leaves, chopped green fodder, etc. were also fed, especially for the herbivorous fishes. The fishes were completely harvested from the ponds after about a year old through netting.

Estimation of operational cost, Income generation and B:C ratio

An economic analysis was conducted to estimate the operational cost involved with the integrated fish-livestock farming systems and the net profit from different treatments. The analysis was based on local market prices for harvested fish and all other items. The net return was measured by deducting the gross cost from the gross return per hectare. The benefit cost (B:C) ratio was also measured as a ratio of net benefit to gross cost.

3. Results and Discussion

The cost of operations involved with integrated fish farming with pig and poultry in 0.025 ha pond is presented in Table 1 and Table 2. Comparatively, total inputs are higher in fish-poultry system than the fish-pig system. Monetary inputs with respect to fish rearing in both the systems are same. The average growth performances of fish and associated livestock in both the systems are presented in Table 3 and Table 4. It is observed that in each of the systems, despite of no commercial fish feed application, the fingerlings exhibited considerable weight gain. The results reveal that pond fertilization from the pig excreta and poultry droppings encourages the growth of tiny plants like algae and other phytoplankton and tiny animals (zooplankton), providing food for the fishes. Amongst the fish varieties tested, Silver carp exhibited highest growth followed by Grass carp and Rohu. This may be attributed to the feeding potential and genetic characteristics of the fishes. However, the fish productivity is greater in the fish-pig system than the fish- poultry system. This result indicates the greater ability of pig excreta in fertilizing ponds than chicken droppings, towards production of phytoplankton and zooplankton. The algae also turn the water green, which makes it harder for predators, such as birds and snakes to see and catch the fish. Comparative effectiveness of the manure on the development of organisms in the food web is also noted by other worker [13] and thus promotion of biological activity in fish ponds is in the order as duck manure > pig manure > raw chicken manure > cattle manure > sheep manure. The pig attained slaughter maturity size (137.12 kg) within a six months time. A stocking density of 10000 number of fingerlings ha^-1 water body within six months gave rise to 9840 kg ha^-1 yr^-1 in fish-pig system while the corresponding value for fish-poultry system was only 8240 kg ha^-1 yr^-1. With the domestic markets for fish expanding the supply of fishes from capture sources cannot meet the demand for fish therefore there is growing opportunities for aquaculture production and this can be achieved faster through integrated fish farming to reduce the gap between supply and demand [14, 15, 16].

The study revealed that the pig excreta act as excellent manure for the fish types tried in the experiment. A famer having a water body of 0.025 ha area generates good revenue from fish, besides earning handsome amount from meat production. The nutrient rich pond water can also benefit the vegetables grown on the pond dike and adjoining area [17], thus the system was found to improve the nutritional security and socio-economic condition of the rural famers of East Kolcho village in Saiha district of Mizoram, North-East India. So, it is suggested that the government should promote livestock-fish aquaculture and remove all bottlenecks so as to improve sustainable rural livelihood and food security [18] in the state.

The economic analysis and benefit-cost (B:C) ratio of practising integrated fish – livestock farming in 0.025 ha pond is presented in Table 5. It revealed that integrated fish-pig farming could generate maximum profit of Rs. 48023.19 per 0.025 ha.yr^-1 with B:C value of 2.04 which was higher than integrated fish-poultry farming system (Rs 33664.06 per 0.025 ha.yr^-1 with B:C value of 1.09).

Table 1. Annual cost of operation for integrated fish-pig farming in 0.025 ha pond in Saiha district of Mizoram, North-East India

Table 2. Annual cost of operation for integrated fish-poultry farming in 0.025 ha pond in Saiha district of Mizoram, North-East India

Table 3. Annual Stocking density, productivity and income generation under fish-pig farming system in 0.025 ha pond at East Kalcho in Saiha district of Mizoram, North-East India

Table 4. Stocking density, productivity and income generation under fish-poultry farming system in 0.025 ha pond at East Kalcho in Saiha district of Mizoram, North-East India

Table 5. Comparative Benefit-Cost (B:C) ratio of integrated fish-livestock farming system in 0.025 ha pond at East Kalcho in Saiha district of Mizoram, North-East India

4. Conclusions

From the findings of the present study, it may be concluded that integrated fish-pig farming is profitable for getting higher growth of fish, net income and optimum utilization of the given resources. The production yields from integrated fish farming vary depending on the livestock (either pig or poultry) and the management system practiced. Nevertheless, it has proved to be more profitable than unitary system of farming and ensures the spread of financial risk, reduced wastes and thus is ecologically more sustainable.

ACKNOWLEDGEMENTS

This study was part of the interventions carried out under National Agricultural Innovation Project (NAIP), Component-III (SRLS) funded by World Bank through Indian Council of Agricultural Research, New Delhi.