Animal Research International

972 – 979

Authors: NWEZE, Nkechinyere Onyekwere

Algae are the chief primary producers in the aquatic environment. Thus, they supply proteins, carbohydrates and mineral salts to the primary consumers and consequently sustain many fishes of commercial interest. Despite algae being a good source of food for some fishes, some cyanobacteria are of low nutritional value and with dinoflagellates may secrete toxins that kill fish. Algae population varies according to seasons and this affects algae - dependent organisms. Optimal algal population is favoured by eutrophication but when there is rapid eutrophication, algal blooms may result. This may lead to the death of zooplankton, game fish and even man. The realization of fish as a major source of protein in Nigeria spurred various workers to investigate the natural food for such fishes as clupeids, Synodontis spp., Chrysichthys spp., Schilbe spp., Tilapia, Alestes, Lates sp. Hydrocynus sp., Siluranodon sp., Eutropus, Bagrus docmac, B. bayad, Heterobranchus sp. Cymnarchus sp., Clarias spp, Hemicynodontus sp. and Brachysynodontis sp. Important fish species cultured in Nigeria include Tilapia nilotica, Tilapia melanopleura, Tilapia galilea, Cyprinus carpio (Common carp), Heterotis niloticus, Lates niloticus (Niger perch), Chrysichtys nigrodigitatus (Catfish) C. gariepinus (Catfish) and others. Aquaculture has not advanced as much in Nigeria as in developed countries where algae could be cultured as feed for fish, shrimps, prawns and other crustaceans in commercial quantities. The economic importance of algae in fisheries cannot be overstressed. Their absence could cause disruption of equilibrium, while excess of them could result to mortality of aquatic fauna.

982 – 986

Authors: ECHI, Paul Chinedu, EYO, Joseph Effiong and OKAFOR, Fabian Chukwuemenam

In ever competitive environment of nature, evolution of most attributes of an organism - anatomy, physiology, and behaviour are determined by the environment through selection. The same is the microhabitats of Sarotherodon melanotheron where three Clinostomatids; Clinostomum tilapiae, Clinostomum complanatum, and Euclinostomum heterostomum, were recovered from Opi Lake (GPS N06.75275*, E007.49104*), were studied from (November 2007– October 2008) using multiple fishing gear techniques; cast nets, hook and line, and seine nets (150 mm – 200 mm), showed significant difference (p < 0.05) in all other anatomical parts but the distance between oral and ventral suckers. The prevalence was low; (20.8 %) was recorded in C. complanatum, (6.4 %) in E. heterostomum and (21.1 %) in C. tilapiae. But mean intensity was high which was suggestive of heavy parasite burden; C. complanatum (2.7), C. tilapiae (5.8) and E. heterostomum (5.1). In the rank-abundance curve for parasite communities C. tilapiae was more abundant than the other two species. Differential parasitic implications was due to selection for relatively better adaptiveness to host’s microhabitats, more population size, better host location, and larger body size. Consequently, this resulted in a trade-off between larger morphometric parts and population size among the parasites.

994 – 1002

Authors: ODO, Gregory Ejikeme, NWAMBA, Helen Ogochukwu and EYO, Joseph Effiong

Studies on some aspects of the biology of Heterotis niloticus in Anambra river were carried out for 22 months. Analysis of the stomach content of 546 species of H. niloticus in Anambra river established the preponderance of plantivorous crustacean, copepods and cladocera throughout the four maturation stages examined. Seasonal variations occurred in the dietary components of the fish. The length-weights relationship and the relative condition revealed that females had better condition. The mean length and weight were 94.5 ± 60 cm (29 – 167 cm) and 120 ± 21.8g (10 – 250g) respectively. A sex ratio of 1:0.8 (M: F) at Otuocha was more pronounced than at Ogurugu and Nsugbe. Digestive enzyme assays in the different gut regions (oesaphagus, stomach, pyloriccaeca, ileum and rectum) of H. niloticus showed an array of glycosidase (amylase, sucrase, malatase, lactase, cellulase); protease, (pepsin, trypsin, chymotrypsin) and lipases. The pattern of spread and relative activity of the enzymes is consistent with its planktophagous diet. Haematocrit values, haemoglobin concentrations, erythrocyte and leucocytes counts, mean cells haemoglobin concentrations, plasma protein, glucose, albumin and inorganic ion (sodium, chloride, calcium, potassium, magnesium, phosphorus) for H. niloticus were established. Correlations were found between some blood parameters and standard length.

1009 – 1018

Authors: AKA, Lawrence Okonkwo and KAMALU, Theodore Nkire

This study describes the effect of intraruminal infusion of different proportions of palmitic (saturated fatty acid) and linolenic (unsaturated fatty acid) on rumen degradability of organic matter fraction of Pennisetium purpureum, total volatile fatty acid and total methane productions in West African Dwarf sheep. Five combination proportions of palmitic and linolenic acids viz: 70 % palmitic acid + 30 % linolenic acid, 30 % palmitic acid + 70 % linolenic acid, 50 % palmitic acid + 50 % linolenic acid, 100 % palmitic acid + 0 % linolenic and 0 % palmitic acid + 100 % linolenic acid designated treatments A-E respectively served as the experimental treatments. These treatments were intraruminally infused into five (5) adult WAD sheep of average body weight of 13.49 ± 1.63 kg and the trial performed in a 5 x 5 latin square experimental design. A sixth group of four sheep, that did not receive any fatty acid infusion, served as the control group. The in-sacco technique for degradability studies was adopted in the determination of organic matter disappearance from the rumen at time intervals of 4, 8, 12, 24 and 48 hours in both the experimental and control groups. Appropriate mathematical model for estimation of total volatile fatty acid (VFA) and total methane production were used for determination of VFA and methane productions. The result of the study showed that organic matter degradability was significantly (p < 0.01) highest in treatment A (70 % palmitic acid + 30 % linolenic acid) at 24 hours (84.63 ± 8.6 %) and 48 hours (88.42 ± 4.8 %) compared to other treatments and the control. Higher proportion of linolenic acid (treatments B and E ) significantly (p<0.01) reduced potential OM degradability at 48 hours with values at 41.08 ± 5.5 % and 23.92 ± 2.4 % respectively. Total VFA production was significantly (p <0.01) increased in treatment A at 24 hours (3.59 ± 0.07 m mol/l) and 48 hours (3.62 ±0.04 m mol/l) compared to other treatments and the control. At same time post incubation, total methane production was significantly (P<0.01) decreased in treatments B (0.39 ± 0.01 mol/hr) and E (0.34 ± 0.006 mol/hr) compared to treatments A (0.52 ± 0.01 mol/hr) which recorded a significant (P<0.01) increase. The study revealed that high proportion of unsaturated fatty acid suppressed rumen fermentation with resultant decrease in organic matter degradability, total VFA and methane productions. The reverse was however the case with high proportions of saturated fatty acids.

1028 – 1034

Authors: ONYECHI, Jacob Okwuchukwu, MARTIN, Gary and MARRIOTT, Chris

A monodisperse aerosol generator (MAGE) was used to generate calibration or monodisperse aerosols containing stearic acid and carnauba wax. Some of the factors affecting the size of aerosol particles generated with the MAGE were determined. The factors include: temperature of operation of the MAGE, type and purity of coating material used. The reproducibility of aerosol particles and stability of the aerosol generated were evaluated. The performance characteristics of the MAGE over an extended period of time of operation were also established. The calibration aerosols generated with the MAGE can be used in situ for studies of aerosol deposition measurement equipment.