Complete Larval Development of the Fresh Water Prawn Macrobrachium vollenhovenii in Cameroon

The African River prawn Macrobrachium vollenhovenii is the largest of the local Palaemonidae prawns along the Cameroonian coast and an important target species for fisheries and aquaculture. A preliminary study on larviculture of this species was carried out at the IRAD-AQUASOL hatchery in Kribi, Cameroon. Berried females M. vollenhovenii were obtained from the Lobe and Lokoundje Rivers in the Southern Region, typical Lower Guinea rainforest streams. The larval rearing system consisted of a single recirculation system of four 65 L cylindrical plastic containers connected to a submerged biological filter container (65 L). Experiments were conducted three times in the same condition, with two batches of larvae reared separately in duplicate per experiment, at a density of 40/L, temperature 26°C, and salinity 16%. Larvae were fed from 1 day after hatching until metamorphosis to postlarvae (PL) with newly hatched Artemia nauplii, three times daily at the rate of 5 nauplii per mL water. The number of newly hatched larvae per female body weight unit was not affected by the female size and ranged between 531 to 1349 larvae g^?1. The six batches succeeded from hatching to metamorphosis, and the 11 distinct larval stages described for M. rosenbergii were found. Larvae in all the batches developed more or less at the same pace up to stage V. However, a clear difference in the timing of appearance of the developmental stages was observed between batches and individuals of the same batch during the subsequent stages. The transition from stage V to stage VI and from stage IX to stage X was longer than the passage to other stages and seems to be the critical rearing period of M. vollenhovenii. From day 20 onward to sampling, the larval stage index (LSI) showed that larval development of the batch 1 was significantly faster than for all other batches. The time for first appearance of postlarvae was variable between batches (41–74 days), and batch 1 larvae passed through metamorphosis within a shorter span of time (41 days). Survival up to postlarvae was variable among batches, ranging between 3%–9%, and was better in batch 1 (9.31 ± 1.09). The general poor performance in terms of survival and metamorphosis rates of larvae seems to be related to the wild condition of broodstock. To improve performance of larvae, domestication of stock may be necessary. This result is the first recorded success in larviculture of M. vollenhovenii in Cameroon.     

Influence of Anaerobic Pre-conditioning on Phosphorus Removal in Swine Manure by Aeration

A feasibility study with three pre-conditioning times was carriedout to examine the effect of anaerobic pre-treatment on phosphorus removal by aeration. The results showed that solublephosphorus could be decreased from 120 mg L^-1 to about40 mg L^-1 within one-day aeration. However, soluble phosphorusconcentration was found not affected by pre-conditioning, butmore pH dependent. Anaerobic pre-treatment significantly increased the uptake of phosphorus by microbes indicated by theincrease in concentration of organic phosphorus fraction. The presence of a large proportion of inorganic insoluble phosphorusconsiderably eclipsed the biological removal of soluble phosphorus, which suggested that the solids/liquid separationbefore aeration could be important to improve the biologicaluptake of soluble phosphorus.     

Nutrient Seepage from Operating Turkey Buildings with a Litter System

The effect of selected nutrient amendments and temperature on the biodegradation of pentachlorophenol (PCP) within a soil biopile was studied on a laboratory scale. This was accomplished by monitoring microbial populations, the concentration of PCP and the release of inorganic chloride ions in the contaminated soil. It was found that temperatures of 10, 15 and 20 °C had no significant effect on microbial populations and the percentage of PCP remaining in the soil. However, the nutrient amendments did have a significant effect on the parameters measured. The dairy manure, ammonium nitrate fertilizer and control treatments all experienced some fluctuations in the amount of PCP remaining in the soil over the incubation period and may have been due to the release of initially unextractable bound residues. PCP decreased by 76% in the municipal solid waste compost amended soil, while the concentration of inorganic chloride ions increased. The municipal solid waste compost treatment had significantly higher bacterial and fungal populations. Based on the results of this study municipal solid waste compost may be used as an effective supplemental nutrient amendment for the degradation of PCP in soil biopiles.     

Conserving the mangrove forest of the Niger Delta

The Niger Delta mangrove forest is the most extensive of such forests in West Africa. Its nature and extent are examined. The potential bio-economic importance of this unique forest type is discussed and proposals are made for an effective regional conservation programme aimed at managing these resources for a sustained yield.     

Influence of Oxalate,Phytate, Tannin,Dietary Fiber,and Cooking on Calcium Bioavailability of Commonly Consumed Cereals and Millets in India

The objectives of this research were to study the bioavailable calcium from widely used cereals and millets by an in vitro method and to provide data on the role of calcium inhibitors. The average total calcium content of the analyzed raw cereals and millets ranged from 10.2 to 324.6 mg/100 g (the lowest and highest values correspond to maize and finger millet, respectively), whereas the rest of the raw cereals and millets had calcium content in the range of 26.3–50.4 mg/100 g, except for rice samples (10.4 mg/100 g). Soluble percentage of calcium is the highest in maize (45.1%), and dialyzable calcium percentage is the highest in wheat (34.9%). The cooking process did not significantly affect calcium bioavailability and the contents of phytate and tannin. However, cooking reduced the oxalate content, and in the case of dietary fiber significant increase was observed. The order of oxalate content in the cereals and millets studied was found to be pearl millet > finger millet > wheat > maize > sorghum > rice. Multiple regression analysis carried out to explain the influence of oxalate, phytate, tannin, and dietary fiber on calcium bioavailability showed greater inhibitory effect of oxalate.     

The effect of dietary protein supplementation on the pathophysiology of Haemonchus contortus infection in West African Dwarf goats

The effect of dietary protein on the pathophysiology of Haemonchus contortus infection in reproducing first pregnancy West African Dwarf (WAD) goats was studied. Eighteen 10-12-month-old pubertal female WAD goats divided into two equal groups were used and confined separately. One group was maintained on high-protein diet (HPD) while the other was maintained on low-protein diet (LPD) from day 1 of pregnancy up to week 6 post-partum. Each animal was infected with 600 infective larvae of H. contortus weekly for 4 weeks and blood collected by jugular venipuncture for the determination of packed cell volume and serum proteins. The results of the study showed that improved protein nutrition significantly enhanced the level of serum albumin (p<0.05). It also significantly lowered the level of serum globulin (p<0.05) that otherwise would be high in haemonchosis. However, improvement in the dietary protein level appeared not to have any effect on the packed cell volume and total serum protein level.     

Investigation of African swine fever in slaughtered pigs,Plateau state,Nigeria, 2004-2006

The occurrence of African swine fever (ASF) DNA in slaughtered pigs in the major pig producing areas of Plateau state over a 2-year period was investigated. Three hundred fifty-nine pig tissue samples from five local government councils (LGCs) were analyzed by clinical signs (C/S), postmortem (PM) lesions and polymerase chain reaction (PCR). The results of diagnosis made by C/S and PM were compared to results obtained by PCR. Out of the 359 abattoir samples, 13 (3.62%) were positive by examination of C/S and PM lesions while 346 (96.38%) were negative. Jos-north LGC had the highest occurrence of PCR positive samples (31 samples); Panyam in Mangu LGC had no positive result. PCR analysis identified 53 positive samples (14.76%); more than 40 were identified on the field. Of the samples, 306 were PCR negative, thus giving a true ASF status of pigs in Plateau state. Analysis of the results, variables involved in the ASF spread and predictable effects of such findings in the pig industry in Plateau state and Nigeria as a whole is discussed.     

Certain factors associated with blister blight resistance in Camellia sinensis (L.) O. Kuntze

The role played by certain factors, physical barriers and chitinase enzyme, associated with blister blight resistance in tea was investigated. The blister blight resistance of the tea clone SA-6 was due to higher amounts of epicuticular wax and increased thickness of cuticle/epidermal layer, functioning as physical barriers to hyphal penetration of Exobasidium vexans. Higher quantum of chitinase in intercellular spaces of palisade tissues was observed in the resistant clone SA-6 through immunolocalization study. Both chitinase assay as well as western blotting studies confirmed that the constitutive level of chitinase expression was higher in the resistant clone when compared with the susceptible tea clone.     

A Paternal Fish Oil Diet Preconception Modulates the Gut Microbiome and Attenuates Necrotizing Enterocolitis in Neonatal Mice

Epidemiology and animal studies suggest that a paternal history of toxicant exposure contributes to the developmental origins of health and disease. Using a mouse model, our laboratory previously reported that a paternal history of in utero exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) increased his offspring’s risk of developing necrotizing enterocolitis (NEC). Additionally, our group and others have found that formula supplementation also increases the risk of NEC in both humans and mice. Our murine studies revealed that intervening with a paternal fish oil diet preconception eliminated the TCDD-associated outcomes that are risk factors for NEC (e.g., intrauterine growth restriction, delayed postnatal growth, and preterm birth). However, the efficacy of a paternal fish oil diet in eliminating the risk of disease development in his offspring was not investigated. Herein, reproductive-age male mice exposed to TCDD in utero were weaned to a standard or fish oil diet for one full cycle of spermatogenesis, then mated to age-matched unexposed females. Their offspring were randomized to a strict maternal milk diet or a supplemental formula diet from postnatal days 7–10. Offspring colon contents and intestines were collected to determine the onset of gut dysbiosis and NEC. We found that a paternal fish oil diet preconception reduced his offspring’s risk of toxicant-driven NEC, which was associated with a decrease in the relative abundance of the Firmicutes phylum, but an increase in the relative abundance of the Negativicutes class.