The production potential of pig manure on fish growth and water quality in integrated pig-fish systems was investigated using effective micro-organisms (Kyusei EM) with or without formulated pig feeds and Anolyte. Both Anolyte and EM effectively reduced faecal bacterial loads in pig manure. EM positively affected pig growth but this was obscured with the introduction from the second month of growth hormone and antibiotics in the pig diets. The application of manure from both treated and untreated pigs had a positive effect on fish yields, improving the feed conversion ratio of the fish to below 2. The EM-A containing manure, however, significantly improved the overall FCR producing a value of 1.4. The application of EM-A containing pig manure also had a marked effect on some faecal organism counts in the manure and in the water of the fish ponds, but also reduced the somatic coliphage numbers significantly. Faecal Streptococci and E. coli found in the kidneys, gills, spleen and liver of the Mozambique tilapia which were used as pond fish, may well have a medium to long term negative implication for the use of animal manures containing faecal bacteria. This aspect required serious attention in future research where agricultural waste products of this nature are used to stimulate fish pond production. Introduction The incorporation of agricultural waste products into integrated aquaculture-agriculture food production systems, the advantages it has in reducing environmental pollution and the beneficial effect such waste products have on fish and crop production, had been practically demonstrated by research and development projects in South Africa and elsewhere (Prinsloo and Schoonbee, 1984 a,b,c; Prinsloo and Schoonbee, 1986: Prinsloo and Schoonbee, 1987; Prinsloo et al., 1999 a, b; Pullen and * All correspondence should be addressed to : Tel. (015) 2682294; Fax. (015)2682294; Email: Koosp@Uni.unorth.ac.za Shedeh, 1980; Edwards, 1991; Diallo, 1992). In recent years, innovative techniques which further positively affected the food production potential of integrated aquaculture-agriculture systems, were developed and applied in other fields of agriculture and environmental quality control (Higa, 1996; Higa, 1998; Sangakkara, 1998). One of these includes the EM Technology (Higa, 1996; Higa, 1998) whilst another, namely Anolyte(Hinze, personal communication) may play an important future role in combatting environmental pollution in intensive food production systems. EM Technology is largely based on the rejuvenation of environmentally contaminated agricultural soils and the establishment of healthy soil conditions by the introduction of beneficial micro-organisms cultured, resulting in the replacement and/or elimination of potentially harmful micro-organisms and insects. At the same time the EM technology can also make a significant contribution towards the reduction and eventual total elimination of pesticides in previously cultivated soils (Parr et al., 1998). By using animal manures in integrated aquaculture-agriculture systems, the problem of nutrient build-up as well as faecal contamination of fish pond water may affect fish production potential of water prior to its use in the irrigation of vegetable crops. It was shown in the literature that fish produced in faecal bacterial contaminated water may be detrimentally affected by the occurrence of faecal Streptococcus belonging to the Lancefield Group D in tissues and organs of rainbow trout Oncorhynchus mykiss ( Walbaum, 1792) (Boomker et al., 1979) but with no apparent affect on Mozambique tilapia Oreochromis mossambicus (Petersen, 1852) and banded tilapia sparmanii (A Smith, 1840). Hoshina et al. ((1958) suggested that these nonhemolytic enterococci may be a strain of Streptococcus faecalis, differing in its relation to its optimum pH and temperature requirements as well as the source from which it has been isolated. Barham et al. (1979) investigated the physiological affects of Aeromonas and Streptococcus infection on rainbow trout, suggest that Aeromonas infection may be of secondary nature following the occurrence of Streptococcus infection. Snieszko and Axelrod (1971) showed that Aeromonas liquefaciens may also cause infectious dropsy and naemorrhagic speticaemia in freshwater fish. The present investigation deals with the following aspects of an integrated pig-fish production system. Different treatments, with and without the inclusion of EM and Anolyte technologies in the prodcution of pigs under controlled environmental conditions were applied. Manures from EM-A treated and untreated pigs, were then used as additional nutrients to promote O. mossambicus’s growth in ponds. This was supplemented by using a formulated pelleted fish diet. Physical and chemical conditions of pond water were also investigated to evaluate nutrient enrichment of pond water by pig manure. The occurrence of faecal bacteria, which included total Coliforms, faecal Coliforms, faecal E. coli, and faecal Streptococci (Group D), in pig manure of the four different experimental groups as well as the fish pond water, were determined. The possible affects of EM-A on specific faecal bacterial loads, are briefly considered, particularly so on Coliphages organisms in the fish pond aquatic environment. Streptococcil infections in kidneys, gills, livers and spleens of O.mossambicus pond fish and possible consequences threof on the fish health status, are considered. Materials Pigs used in the Investigation and Methods A total of 40 mixed bred pigs (50 percent Duroc, 25 percent Landras, 25 percent Large White = F2) devided into four groups were obtained from the Mockford Farms, Pietersburg, The pigs were divided into 4 groups of 10 pigs each and housed in newly constructed disease free pig sties at a density of one pig/m. Unlimited water was supplied to each unit using drinking nipples. Pigs were fed ad lib, making use of commercially available pig feed troughs. Commercial diets were applied.

Integrated aquaculture-agriculture production systems were developed primarily for sustainable food production in rural areas of South Africa. The problem of environmental pollution was addressed by utilizing the nutrients in the agricultural waste products to fertilize the fish ponds, thus stimulating pond productivity and releasing nutrients such as nitrogen and phosphorus into irrigation water for vegetable crop production. Due to problems encountered with soil quality as a result of the build-up of nutrients due to chemical fertilizers and the excessive use of pesticides, it was decided to implement EM technology to restore the organic and micro-biological balances of the cultivated lands. Three vegetable crops, namely cabbage, spinach and lettuce, were cultivated under different irrigation systems, using EM, organic compost and inorganic chemical fertilizing programmes. After the first application of EM Bokashi, significant improvements in vegetable yields were recorded. EM treated plots proved to be superior in the yields of cabbage and lettuce clearly exceeding the agricultural average for South Africa. In the case of spinach, EM treated plots under drip irrigation proved to be the most productive. Application of irrigation water as well as soil quality, appeared to be two factors that must be considered when ascertaining the amount of EM to be applied to further improve yields following organic fanning. Recommendations are made to evaluate the health status of EM treated soils.

A comparison is made of the water efficiency of two types of drip-irrigation systems and one micro- and one flood irrigation system, using nutrient-enriched water, in the production of selected vegetable and maize crops. Results showed the micro- and drip-irrigation systems to be the most economical in terms of water usage. Of these, the drum-drip-irrigation system was the most efficient and probably the system of choice to be developed further for community-based sustainable food production systems in predominantly rural areas of South Africa.

An investigation into the growth and production of the sharptooth catfish Clarias gariepinus (Burchell) was conducted over a period of 75 d in recirculating water, using three types of biofiltration systems. Yields fluctuating between 195.2 kg and 242.1 kg were obtained with the mean fish mass per m of water ranging between 19.5 and 22.5 kg. A biofilter system using PVC shavings was not only found to be the most efficient in the transformation of nitrogenous wastes, but also produced the highest growth and production of catfish as well as the best feed conversion ratio of the three biofiltration systems used.

The incorporation of laying hens in an integrated aquaculture-agriculture family-based food production unit, was investigated. The Hyline-silver laying hen hybrid was found to be extremely suitable with an exceptionally high egg production as well as a 100% survival rate over more than 200 d. Fish used included the sharptooth catfish Clarias gariepinus and the three-spot barb Barbus trimaculatus, both stocked at a relatively low density. Fish yields were satisfactory without any supplementary diet. Water quality conditions were generally good with no signs of oxygen depletion. Problems were encountered with fungal diseases amongst some of the vegetable crops during the wet season of the summer-autumn cycle. Recommendations are made to remedy the problems encountered and to improve fish yields.

A comparison is made of the relative efficiencies in the breakdown of nitrogenous wastes of three types of water recirculation biofiltration units used during the production of the sharptooth, catfish Clarias gariepinus (Burchell). Two types of trickling filters were employed. One contained PVC shavings with a calculated surface contact area of 1 220 m(2). The second is a more sophisticated biofilter unit made up with Siporax porous sintered glass cylinders with a total surface water contact area of 32 000 m(2). The third filter consisted of a rotating biological contactor unit with a water contact surface area of 271.2m(2). Investigations showed that the PVC shavings filter unit was clearly the most efficient of the three by transforming more than 96% of the NH3-N into NO3-N. This was followed by the rotating biological contactor with a 93% efficiency and lastly by the Siporax filter with an almost 93% efficiency. The outcome of the section on the production of Clarias gariepinus follows in Part 2 of this series.

An investigation was made into the growth and production of Peking and Muscovy ducks on ponds using nutrient-enriched water from a water-recirculating intensive fish production system. The same water which received additional nutrients during a duck feeding programme was then used to irrigate selected vegetable crops. The production potential of Peking and Muscovy ducks was evaluated and the yields of different vegetable crops were compared with each other as well as with yields obtained during standard production practices. The application of this type of integrated aquaculture-agriculture system in rural areas as part of family-/community-based food production schemes is discussed.

As intensively cultured fish usually require high protein feeds, and since feeds are normally the largest variable cost item in commercial production, the profitability of intensive aquaculture is closely related to the world supply and cost of feed protein. Traditionally fish meal has been the major component of all fish feeds. However, its high cost has necessitated a search for alternative protein sources, especially those that are not suitable for human consumption. This study investigated the partial replacing of fish meal with alternative protein sources (tomato waste, soybean meal, brewers yeast) in iso-nitrogenous diets of C. gariepinus. The tomato used consisted of sun-dried pips and skins from ripe tomatoes used in the production of tomato pastes. The soybean consisted of either dehulled, solvent-(hexane) extracted soybean meal (Soy-2) or the same soy meal that had undergone a further extrusion process (Soy-1). The yeast used was a waste product from a local brewery. A final diet consisting of a mixture of the various ingredients was also prepared. Twenty-five catfish (30 to 45 g live mass (LM)) were randomly allocated to 24500 l tanks and four tanks were allocated to each diet. The tanks were then connected to a recirculating system (13000 l total volume) and each had a flow rate of 7 +/- 1 l min(-1). The water temperature was maintained at 25 +/- 1 degrees C. The total biomass in each tank was measured weekly and the feed adjusted accordingly. The catfish were fed at 5% of total biomass for the first 4 d and 6% for the last 3 d of the week. The experiment was terminated after a 60 d feeding period. A statistical comparison of the final mean mass showed that all the diets differed significantly from each other (p=0.05), with the exception of the yeast and mixture diet and the yeast and Soy-1 diet. The descending ranking order of the mean final body mass (LM +/- standard error, g) of the various diets was as follows: fish meal (284.6 +/- 5.2), tomato (261.9 +/- 5.3), yeast (222.2 +/- 5.7), Soy-1 (220.5 +/- 5.2), mix (201.4 +/- 5.5), and Soy-2 (115.3 +/- 5.5). The relatively strong growth experienced by fish receiving the tomato diet could possibly be caused by the high fish meal content of this diet. The poor growth of the Soy-2 diet is attributed to a high urease activity index (1.73). Soy-1 had an index of 0.07. The growth experienced by catfish fed the various protein sources indicates that C. gariepinus are able to utilise alternative protein sources successfully.

Summary We studied allozyme polymorphism and its relation to morphological characteristics in 122 individuals from four lines of African catfish. Starch gel electrophoresis was used to screen 26 loci, of which five were polymorphic. Average heterozygosity levels differed moderately among lines (range 4–6.3 %) and were closely related to the management histories of the populations studied. Significant differences between the allelic frequencies of strains were found at all polymorphic loci, and gene products of glucose-6-phosphate isomerase (E.C. 5.3.1.9) proved particularly suitable for differentiation among the four strains studied. There was little evidence for linkage between heterozygosity values and specific quantitative morphological characteristics. However, a significant positive correlation between heterozygosity and variation within the morphological parameters involved was found in several instances.

The skin and muscle chemical comparisons from normal and golden coloured African sharptooth catfish, Clarias gariepinus, of two different size (± 360 and ± 1500 g live mass) groups are reported. The skin of the golden strain is shown to be that of an albino that contains no melanin. Size has a stronger influence than strain on the proximate, fatty acid, amino acid and mineral profiles of both the skin and muscle. For both strains, the larger size class had statistically (P > 0.05) lower muscle moisture and higher total lipid content than the smaller size class. There was no significant difference in the muscle protein content (16.7–17.6% wet mass basis) between and within the strains and size classes. The skin has higher concentrations of glycine, proline and hydroxyproline than the muscle. The major fatty acids in both the skin and muscle were palmitic (> 23%) and oleic (>28%). Of the muscle minerals, potassium was significantly (P > 0.05) higher in the larger size class for both strains. The lack of any tangible difference in the muscle chemical composition of both strains therefore makes the golden catfish strain more attractive for the fresh fish consumer.

The influence of various lipid sources on the muscle fatty acid composition of juvenile African sharptooth catfish Clarias gariepinus, was tested Juveniles were fed an artificial diet,for 60 days, containing no lipid (Al control), or the following lipids at 10% of the diet, sunflower oil (B, a high level of C18:1 omega 9 and C18:2 omega 6), cod liver oil (C, a high level of 20 and 22 C omega 3 fatty acids) and tallow (D, predominantly SFA and MUFA). The best growth was achieved by fish fed the sunflower diet. Muscle total lipid composition was strongly influenced by diet and contained the following SFA, MUFA and PUFA percentages, and a omega 3/omega 6 ratio of A, 36.33; 45.13; 15.70% & 0.52; B, 30.78; 34.54; 33.96% & 0.11; C, 33.51; 38.75; 24.59% & 1.87; D, 38.87; 46.03; 13.06% & 0.44, respectively.

The fatty acid profile of four different genetic strains of Clarias gariepinus: gold (G), Netherlands (N), RAU (R) and Wild (W) were evaluated. Fertilised eggs and larvae of the four strains were maintained under identical environmental conditions. After nine weeks, the two faster growing strains (G and W) had less total body lipid than the others (N and R). The total saturated (SFA), monounsaturated (MUFA) and polyunsaturated (PUFA) fatty acids of the four strains were: G - 32.1; 26.8 and 37.9%; N - 33.5; 27.8 and 35.5%; R - 32.7; 29.0 and 35.4%; W - 32.91 27.7 and 36.8%, respectively. The major fatty acids that showed statistically significant differences between strains were: C16:0, C18:1 omega 9, C22:5 omega 3 and C22:6 omega 3. The G strain had a significantly higher omega 3/omega 6 ratio (2.2) compared to that of the other strains (N - 1.9; R - 1.9 and W - 1.9). In a second trial, juveniles of strain G were fed an artificial diet for 60 days containing no lipid (A, control), or the following lipids at 10% of the diet, sunflower oil (B, a high level of C18:1 omega 9 and C18:2 omega 6), cod liver oil (C, a high level of 20 and 22 C omega 3 fatty acids) and tallow (D, predominantly SFA and MUFA). Muscle total lipid composition was strongly influenced by diet and contained the following SFA, MUFA and PUFA percentages, and a omega 3/omega 6 ratio of: A - 35.9; 45.3; 15.0% and 0.5; B - 30.6; 33.4; 33.6% and 0.1; C - 33.2; 37.2; 23.6% and 1.8; D - 38.7; 45.3; 12.1% and 0.4, respectively.

The larval growth potential of four African sharptooth catfish strains over a 56 day growth period was evaluated and found to differ significantly between strains. Strain strongly influenced body total lipid, but not body protein content. Body total Lipid content was associated with growth rate. The body amino acid content was not strongly influenced by strain. Strain had an influence on total body lipid fatty acid composition, although no fixed trend was established. Although strain influenced the body mineral profile, no fixed trends were manifested.

Summary The replacement of fish-meal (two sources, arbitrarily designated FMA and FMB), with either freeze dried (GVD) or oven dried (GOD) gonads of Clarias gariepinus in a starter diet for larvae of this species, was tested. No significant difference in larval growth rates was noted between the various protein sources, although fish receiving FMA had a significantly lower final body weight (p ≤ 0.05). Fish which received gonads as a protein source had a significantly higher total body lipid (GOD = 28.47% Dry Mass—DM) than those receiving fish-meal (FMA = 13.97% DM). The whole body fatty acid composition was influenced by that of the fatty acid composition of the protein source. The hepatocytes of the fish receiving the gonads as protein source showed 100% lipid accumulation and degenerative changes, whilst those from fish-meal fed fish showed none.

The effect of increased Vaal River total dissolved salts (TDS) concentrations was investigated on algal growth and photosynthetic rates of 3 different algal species i.e. Cyclotella meneghiniana Kutz., Monoraphidium circinale (Nyg.) Nyg. and Microcystis aeruginosa Kutz. The algal species were introduced to different Vaal River salt concentrations in a GBG-11 growth medium for a period of 14 d. The salt concentrations varied between 100 mg.l-1 and 2 000 mg.l-1. Turbidity was used as a measure of growth. On day 8 of the experiment, water samples were taken and chlorophyll-a was measured as well as primary productivity by the C-14-uptake method (acid-bubbling). With increased TDS concentrations, the growth of C. meneghiniana and M. aeruginosa was inhibited, but the growth of M. circinale was unaffected. With increasing salinity concentrations the chlorophyll-a concentration in C meneghiniana, M. aeruginosa and M. circinale increased up to salinities of 250 mg.l-1 and then decreased at salinities of between 500 mg.l-1 and 2 000 mg.l-1. The carbon assimilation rate of C meneghiniana and M. aeruginosa increased with an increase in TDS concentration, and that of M. circinale was very low at salinities of 250 mg.l-1 and above. These results show that if the salt concentration of the river increases with time, algal species that can adapt to a much wider range of salinities may become dominant, e.g. M. circinale. C meneghiniana and M. aeruginosa, on the other hand, can be expected to be eliminated from the water under conditions of increased salinity.

Humidity chamber, MariSource hatching-tray and ''Zuger'' glass funnel incubation systems were compared for hatching successes of both Cyprinus carpio and Clarias gariepinus fertilised eggs. The humidity chamber incubation system proved superior for C. carpio, whilst the MariSource hatching-tray system was better for C gariepinus. Fungal infections greatly influenced hatching results.

The two fish species Clarias gariepinus and Cyprinus carpio were produced in poly- and monoculture in final effluent sewage maturation pond water. Yields of more than 6 t of fish-ha-1 were obtained in polyculture within a 100-d production period using overwintered juvenile stock. Late summer production under monoculture conditions for each species was, however, less favourable partly due to the water temperatures which dropped to below 20-degrees-C and the use of juvenile fish bred during the same season. The investigation showed that sewage effluent water can be used to obtain good fish yields using the two species C. gariepinus and C. carpio in polyculture.

The chemical control of Xenopus laevis tadpoles, under laboratory conditions, was tested using different concentrations of chlorine. Simultaneously, the toxicity of chlorine to Clarias gariepinus juveniles was investigated. X. laevis was more sensitive to chlorine concentrations, with 100% mortality occurring at 0,5 mg/l (tap water) and 12,0 mg/l (pond water and acidified pond water), whilst for C. gariepinus juveniles, this only occurred at 5,0 mg/l (tap water) and 12,0 mg/l (pond water and acidified pond water), respectively. The residual toxicity of chlorine sharply decreased after 72 h.Die chemiese beheer van Xenopus laevis paddavisse is met behulp van verskillende konsentrasies chloor onder laboratoriumtoestande vasgestel. Terselfdertyd is die toksisiteit van chloor vir jongvis van Clarias gariepinus bepaal. X. laevis was meer sensistief vir chloor, met 100% mortaliteite by 0,5 mg/l (kraanwater) en 12,0 mg/l (dam- en aangesuurde damwater) as C. gariepinus jongvis, waar onderskeidelik 5,0 mg/l (kraanwater) en 12,0 mg/l (dam- en aangesuurde damwater) daarvoor benodig was. Die residuele toksisiteit van die chloor het drasties verminder na 72 h.

Use is made of plastic covered wire mesh cages to minimise the stress and physical damage caused by the inherent aggression of Clarias gariepinus during the spawning phase. The cages enable a single person to perform the entire hormonal injecting programme with a minimum of stress in a relatively short period of time.