Use of chrmical or hiologicaljsh silugr as feed for Chrysichthys nigrodigitatus (Bugridue).These studies were undertaken to test the nutritional value of marine fish offal products prescrvcd by different silage nlethods and used as an ingredient in african catfish (Clzry.sichthys nigrodigitutus) feeds. The first experiment concerned cooked tuna wastc silage preparcd by addition of 3% formic acid. After incubation for 16 days, a desirablc and stable pH of 4.03 was obtained. The hydrolysate, containing 66.7% of crude protein (N x 6.25) on a dry matter (DM) basis, was incorporated with a basal mixture to formulate feeds containing 38% crude protein which were fed to Chrysichthys nigrodigitatus. A commercial fish meal was uscd as control on an iso-nitrogenous basis. Diets were distributed to 6 groups of 50 catfish of an initial weight of 34 g for 56 days at 3/70 (dry) of fish body wcight. The zootcchnical performances obtaincd with fish fed with the expcrimental diet (CNE) were bcttcr in terms of the daily weight gain (0.86 g.d-'), food conversion ratio (FCR: 1.79) and protein cfficiency ratio (PEU: 1.46), compared to those of the control diet (no significant differencc). During the second experiment, fish silage was preparcd by fermentation with 65% (wct weight, wlw) cooked and ground small sardines, 25% (wlw) corn flour, 5% sugar and 5% (wlw) fcrmented cassava used as fermentation startcr. After 35 days, a stable pH of 4.1 8 was attained and the source of Sermentation substrate did not affect the nitrogen content of the hydrolysate aftcr 15 days storage. The liquid silage (cosilage) containing 35.65% crude protein (DM) was also added to a mixture and tested against control fish meal on an iso-nitrogenous basis in experimental conditions identical to those described above. The incorporation of cosilage in the diet (CE) resulted in an increase in the daily weight gain (0.94 g.d-'), FCR (1.77) and PER (1.61) compared to control diet.In both experiments, the increase in growth rate and the presence of greater amount of lipids in the body of fishcs receiving silage are partially due to greater food ingestion, owing probably to a different texture of the pellets or the possible presence of food attractants. The acceptability of fish silage as an ingredient in catfish feed, as shown in these studies, constitutes an alternative to fish meal in utilizing marine fish waste or low value fish.Keywords: Chrysichthys nigrodigitatu.~, catfish, feeding, growth rate, tropical aquaculture, Côte d'Ivoire.Deux expériences ont été réalisées pour tester la valeur alimentaire, pour le mâchoiron (Chrysichthys nigrodigitatus), de dérivés de poissons de mer conservés par la méthode de l'ensilage. Le premier essai a concerné des déchets de conserveries de thons conservés par la méthode de l'ensilage acide (3 % d'acide formique). L'hydrolysat, renfermant 66,7 % de protéines brutes (N x 6,25) sur la base de la matière sèche (MS) a été incorporé dans un aliment expérimental en substitution à la farine de poisson sur une base iso-azotée. Les al...
The parameters of growth, mortality, the exploitation and the recruitment of Atya scabra (Leach, 1815) as traditionally fished in the Bia river, were studied. These parameters were determined from the size frequencies by the FiSAT II software. The results obtained at the specimens of Aboisso were:= 156,45 mm, K = 1,50 year -1 , Φ' = 4,56, Z = 5,72 year -1 , M = 1,48 year -1 , F = 4,24 year -1 and E = 0,74 year -1 . In Biaka, the estimated values were: L = 140,7 mm, K = 0,68 year -1 , Φ' = 4,13, Z = 1,52 year -1 , M = 0,91 year -1 , F = 0,61 year -1 and E = 0,40 year -1 . Aboisso specimens have a higher growth performance index (Φ') than Biaka's and a weak longevity (tmax = 2 years) compared to Biaka (tmax = 4.41 years). Shrimps are under exploited in the locality of Biaka (E <0.5) but overexploited in Aboisso (E> 0.5). Total mortality is higher in Aboisso than in Biaka. However, the survival rate recorded in Aboisso (S = 0.003 years) is lower than that of Biaka (S = 0.22 years). Recruitment is continuous throughout the year, with two peaks (a major peak in September and a minor European Scientific Journal April 2017 edition Vol.13, No.12 ISSN: 1857 -7881 (Print) e -ISSN 1857 85 peak in February) in Aboisso. As for Biaka, the presence of a normal distribution indicates that recruitment is single. These results will serve as a database for rational management of A. scabra. Keywords
La zone de marnage du lac de Buyo est devenue le site d’intenses activités agricoles avec utilisation de pesticides pour optimiser la production. Une enquête socio-démographique des agriculteurs a été réalisée afin de prendre en compte l’âge, le genre, le niveau d’instruction, les encadrements, les équipements de protections individuelles (EPI) et les pesticides utilisés pour identifier des matières actives. Pour 323 producteurs enquêtés, les résultats révèlent que 35 % des hommes ont plus de 55 ans, 98% des femmes et 77% des hommes sont des non scolarisés. L’encadrement des paysans par les structures étatiques est très faible avec 71,21% d’agriculteurs non formés, ce qui explique le pourcentage de 26,32% de personnes utilisant les équipements de protections individuelles. Le risque de contamination sanitaire et environnemental est autant plus élevé en raison de la rémanance et la dangerosité des pesticides identifiés comme le Degesch (phosphure d’aluminium) considéré très dangereux (classe Ib) par l’OMS et ceux de la classe II et III . En effet les producteurs n’observent pas les bonnes pratiques phytosanitaires et cela aura pour conséquence la contamination de l’eau et des ressources aquatiques par les résidus de pesticides. The Lake Buyo tidal zone has become the site of intense agricultural activities with the use of pesticides to optimize production. A socio-demographic survey of farmers was carried out to take into account age, gender, level of education, management, personal protective equipment (PPE), and pesticides used to identify active ingredients. For 323 producers surveyed, the results reveal that 35% of men are over 55 years old, 98% of women and 77% of men are uneducated. The supervision of farmers by state structures is very weak with 71.21% of farmers not trained, which explains the percentage of 26.32% of people using personal protective equipment. The risk of health and environmental contamination is even higher due to the persistence and dangerousness of pesticides identified as Degesch (aluminum phosphide) considered very dangerous (class Ib) by the WHO and those of class II and III. Indeed, producers do not observe good phytosanitary practices and this will result in the contamination of water and aquatic resources by pesticide residues.
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