Thesis (PhD)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: This study investigated the “Effect of Phytogenic Feed Additives on Gonadal Development in Mozambique tilapia (Oreochromis mossambicus). Aquaculture remains the fastest growing animal food-producing sector and it is set to overtake capture fisheries as a source of food fish, and also to outpace population growth. This rapid growth can be attributed to the increasing demand for aquaculture products, and an urgent need for a sustainable food resource and the safe production of food. Globally, fish provides over 3.5 billion people with up to 15 percent of their average per capita intake of animal protein. The introduction of aquaculture to sub-Saharan African (SSA) took place during the 1940s and 1950s, and the main objectives were to improve nutrition in rural areas, allow for the diversification of activities to reduce the risk of crop failures, to generate additional income, and to create employment opportunities. Aquaculture was seen as a viable option for rural development in SSA, and substantial resources were invested to support its development. Poor results were however, recorded in terms of production and sustainability. Tilapia is the most widely cultured of all fish species farmed, and the second most important group of freshwater and brackish water fish after carps. Tilapia has all the necessary traits that makes it an excellent species to culture, but costefficient production is hampered by the animals attaining sexual maturity at a an early age, which then result in precocious breeding in aquaculture systems. The production of single-sex populations (i.e. all male) is a potential means to address the problem of precocious breeding, but the technologies used to establish single-sex populations are not readily available to resource-poor communities that farm with tilapia for food purposes. Phytochemicals, also known as phytoestrogens, are plant-derived compounds that structurally or functionally mimic mammalian estrogens that affect the sexual differentiation of fish. Phytochemicals occur in plants like Pawpaw (Carica papaya) and Moringa (Moringa oleifera). The study thus had a threefold objective. Firstly, the study investigated the potential of Pawpaw seed meal (P) and Moringa seed meal (M), as part of a commercial tilapia diet, to be used as endocrine disrupting compounds (EDC’s) to control the reproduction of sexually mature Mozambique tilapia (20-45g). Secondly, assess the potential of P and M to inhibit the attainment of sexual maturity in immature tilapia (2-8g). Finally, P and M to determine its influence on sexual differentiation of tilapia fry (9-12 days posthatch) to produce all-male populations. The study indicated that both P and M seeds contain bio-active chemicals that are capable of disrupting the gonad function, differentiation and sexual maturation of Mozambique tilapia. Sperm production was affected, evident in the degeneration of the testicular tissue samples. Egg production, ovulation and spawning were all affected, as evident in the difference in colour of the degrading eggs, as well as the absence of spawning. Ovo-testes were observed in cases where diets containing 10.0g P and 10.0g M /kg basal diet were fed. Eggs were observed in the ovaries of sexually immature fish, but spawning did not occur. The study also presents the first report on the isolation of Oleanolic acid in Moringa seeds. The evident of antifertility properties of both Pawpaw and Moringa seeds can be exploited to control or prevent reproduction of Mozambique tilapia in SSA aquaculture systems. This could be of particular importance to aquaculture development in rural areas of Sub-Saharan African countries, given the abundant year round availability of these compounds. Further studies are required to optimise the preparation of the experimental compounds; as well as determining the optimal inclusion level of the phytogenic compounds, as well as how their efficacy to manipulate the reproductive potential and ability of Mozambique tilapia are influenced by environmental factors such as water temperature. / AFRIKAANSE OPSOMMING: Akwakultuur is die vinnigste groeiende dierlike voedsel-sektor. Daar word verwag dat dit visserye sal oortref as ʼn bron van voedsel en dat groei in dié bedryf selfs die bevolkingsgroei sal verbysteek. Die vinnige groei in die sektor kan toegeskryf word aan die toenemende vraag na akwakultuur produkte en 'n dringende behoefte vir 'n volhoubare voedsel hulpbron, wat ook die veilige produksie van voedsel sal verseker. Wêreldwyd voed vis meer as 3.5 miljard mense en dra tot 15% van die gemiddelde hoeveelheid dierlike proteïen per kapita ingeneem, by. Die bekendstelling van akwakultuur in sub-Sahara Afrika (SSA) het gedurende die 1940's en 1950's plaasgevind, met die belangrikste doelwitte om voeding in landelike gebiede te verbeter, geleenthede vir diversifisering te skep wat die risiko van misoeste verminder, om bykomende inkomste te genereer en werksgeleenthede te skep. Akwakultuur is gesien as 'n lewensvatbare opsie vir die ontwikkeling van die landelike gebiede in SSA en aansienlike hulpbronne is belê om die ontwikkeling daarvan te ondersteun. Swak resultate is egter in terme van produksie en volhoubaarheid behaal. Tilapia is die mees algemene spesies wat gekweek word en is die tweede mees belangrike groep van varswater en brak water vis soesies, na Karp. Tilapia beskik oor al die nodige eienskappe wat dit ʼn uitstekende spesie vir voedselproduksie maak, maar koste-doeltreffende produksie daarvan word gekortwiek deur die feit dat die spesie seksuele volwassenheid op 'n vroeë ouderdom bereik, wat dan lei tot vroeg-rype teling en die gevolglike oorbevolking en swak groei van tilapia in ʼn akwakultuur sisteem. Die produksie van enkel-geslag bevolkings (d.i. slegs manlike vis) is ʼn potensiële oplossing vir dié probleme, maar die tegnologie wat gebruik word om enkel-geslag bevolkings te produseer is nie geredelik toeganklik vir hulpbron-arme gemeenskappe wat met Tilapia vir kosdoeleindes boer nie. Fitochemikalieë, anders ook bekend as fito-estrogene, is verbindings wat in plante voorkom en wat struktureel of funksioneel die werking van die natuurlike soogdier estrogene/androgene naboots, met die fitochemikalieë wat die seksuele differensiasie van vis beïnvloed. Fitochemikalieë kom in plante soos papaja (Carica papaya) en Moringa (Moringa oleifera) voor. Die studie het dus gepoog om die potensiaal van papaja saad meel (P) en Moringa saad meel (M), as deel van 'n kommersiële tilapia dieet, om as endokriene ontwrigters (EDC's) gebruik te word om die reproduksie van seksueel volwasse Mosambiek tilapia (20-45g) te beheer, om te voorkom dat onvolwasse tilapia (2-8g) geslagsrypheid te vroeg bereik en ook om die geslagsdifferensiasie van tilapia vingerlinge (9-12 dae na uitkom) te manipuleer om enkel-geslag (manlike) produksiegroepe te produseer. Die studie het aangedui dat beide papaja en Moringa sade bio-aktiewe chemikalieë wat die werking van die gonadotrofien hormone, geslagsdifferensiasie die stadium waarop Mosambiek tilapia geslagsrypheid bereik, kan beïnvloed. Spermproduksie is negatief beïnvloed, soos waargeneem in die degenerasie van die testisweefsel. Eierproduksie, ovulasie en die vrystelling van eiers is almal negatief beïnvloed, soos duidelik waargeneem in die kleurverskil (van normale eiers) van eiers wat ʼn mate van reabsorbsie aandui en die feit dat geen eiers vrygestel is nie. Ovo-testes is waargeneem in gevalle waar diëte met 10.0g papaja en / of Moringa / kg basale dieet gevoer is. Eiers is waargeneem in die eierstokke van seksueel onvolwasse vis, maar vrystelling het nie plaasgevind nie. Die studie is die eerste verslag oor die isolasie van Oleanoliese suur in Moringa sade. Die duidelike reproduksie-beperkende (anti-vrugbaarheid) eienskappe van beide papaja en Moringa sade kan benut kan word om reproduksie in Mosambiek tilapia te voorkom of te manipuleer in SSA akwakultuur stelsels. Dit is veral van besondere belang vir akwakultuur ontwikkeling in die landelike gebiede van SSA lande, gegewe dat beide sade regdeur die jaar geredelik beskikbaar is. Verdere studies word benodig om protokolle vir die voorbereiding van die eksperimentele verbindings te optimaliseer, sowel as die bepaling van die optimale insluitingsvlakke van die fitogeniese verbindings, asook hoe die doeltreffendheid van hierdie verbindings deur omgewingsfaktore soos water temperatuur beïnvloed word. / The University for Development Studies (UDS), Ghana, particularly Prof S.K. Nokoe, and Ghana Education Trust Fund (GETFund), for the initial financial support that enabled me to enrol for the programme. The Division of Aquaculture, together with the Postgraduate and International Office (Postgraduate Funding Section), Stellenbosch University (SU) for financial support during my studies.

No description available.

Os aditivos alimentares monensina e óleos funcionais foram avaliados em dietas com elevada proporção de concentrado fornecida de forma abrupta a 12 novilhos canulados no rúmen. Foi utilizado delineamento de blocos ao acaso com medidas repetidas no tempo em dois períodos experimentais de 21 dias, com no mínimo seis semanas para readaptação dos animais à dieta volumosa (feno de Tifton). A dieta basal composta por 92,25% de concentrado (82,41% de milho quebrado, 6,78% de farelo de soja, 7,75% de feno de Tifton picado, 1,77% núcleo mineral e 1,29% ureia) foi fornecida no dia 1 de cada período experimental. Os animais receberam um dos aditivos alimentares, como seguem: sem aditivos (CTR), 400 mg de óleos funcionais de mamona e líquido da casca de caju/kg de MS ingerida (OF), 30 mg de monensina/kg de MS ingerida (M30) e 40 mg de monensina/kg de MS ingerida (M40). As variáveis ruminais e sanguíneas, o comportamento ingestivo e os microrganismos ruminais foram avaliados. Cada novilho foi considerado uma unidade experimental. Os dados foram analisados com o Proc Mixed, tendo o tempo após o fornecimento da alimentação como medidas repetidas. Animais alimentados com M40 reduziram a concentração total de ácidos graxos de cadeia curta (P = 0,017), a concentração de lactato (P = 0,0012) e osmolaridade ruminal (P = 0,04). Houve interação entre tratamento e dias após transição abrupta sobre a ingestão de matéria seca expressa em kg/dia (P = 0,008) e peso corporal (P = 0,045), bem como para o pH médio do rúmen (P = 0,04), a proporção molar de propionato (P = 0,034) e a proporção molar de valerato (P = 0,031). O tratamento M30 apresentou a menor relação acetato:propionato (P = 0,03). Os tratamentos não alteraram o comportamento ingestivo (P ≥ 0,05) ou as atividades comportamentais (P ≥ 0,05), bem como a expressão relativa de F. Succinogenes (P = 0,465), S. bovis (P = 0,781) e M. elsdenii (P = 0,972). O tratamento CTR apresentou maior propensão à ocorrência de desbalanço no sistema ácido-básico do sangue. Porém, o volume globular sanguíneo, o pH e a osmolaridade do sangue não foram alteradas pelos tratamentos (P ≥ 0,05). Os aditivos alimentares utilizados em dietas com elevada proporção de concentrado fornecidas de forma abrupta agiram sob formas distintas na redução da acidose subclínica. De forma geral, a inclusão de OF e M40 não resultou em melhoria expressiva no ambiente ruminal diante da situação desafiadora da dieta, especialmente na primeira semana, quando o tratamento M30 apresentou melhor capacidade de estabilizar a fermentação ruminal. / Monensin and functional oils were evaluated in high-concentrate diet abruptly fed to 12 ruminally canullated steers. A randomized complete block design with repeated measures over time within two experimental periods of 21 days each was used, with at least six weeks for readaptation of steers to forage diet. In the high-concentrate basal diet (92.25% of concentrate) the follow treatments were added: no additives (CTR); 400 mg of castor oil and cashew nut shell liquid/kg of DMI (FO); 30 mg monensin/kg of DMI (M30) and 40 mg monensin/kg of DMI (M40). The ruminal variables, blood metabolites, feeding behaviour and microbial variable were determined. Each steer was analysed as an experimental unit. Data were analysed by Proc Mixed with time after feeding used as repeated measures.Treatment M40 showed lower ruminal total short chain fatty acids (P = 0.017), lactate concentration (P = 0.0012) and osmolality (P = 0.04). The dry matter intake expressed by kg/day (P = 0.008) and porcenteage of body weight (P = 0.045), as well as mean rumen pH (P = 0.04), propionate (P = 0.034) and valerate (P = 0.031) molar proportion had significative interaction between treatment and day. The treatment M30 showed lower acetate:propionate ratio (P = 0.03). Treatments did not change the feed behaviour (P ≥ 0.05), behavioural activities (P ≥ 0.05), and relative expression of Fibrobacter succinogenes (P = 0.465), Streptococcus bovis (P = 0.781) and Megasphaera elsdenii (P = 0.972). The blood packed volume cell, osmolality and pH were unaffected by treatments (P ≥ 0.05), but high propensity to systemic acid-base imbalance were observed in CTR diet. Feed additives had different effects to reduce the subacute acidosis. The use of FO and M40 did not change most of the rumen fermentation variables, especially in the first week after abrupt transition, where M30 provided higher protection against acidosis.

Resumo: O presente ensaio de pesquisa objetivou avaliar o preparado de anticorpos policlonais contra as bactérias ruminais precursoras de distúrbios nutricionais (Streptococccus bovis, Lactobacillus ssp. e Fusobacterium necrophorum) na forma sólida, como aditivo alimentar preventivo à acidose ruminal em bovinos e substituto à monensina. Nove vacas canuladas no rúmen com 677±98 kg de peso vivo médio foram agrupadas em baias individuais através de delineamento inteiramente casualizado com dois períodos de 20 dias. Separaram-se os animais em três tratamentos: controle (CTL), preparado de anticorpos policlonais (PAP) e monensina sódica (MON). Nos primeiros cinco dias de cada período, os animais receberam apenas cana e úreia como alimento. Em seguida, foi fornecida a dieta desafio com aproximadamente 74% de concentrado por 15 dias, com o intuito de causar acidose ruminal. Houve um tempo de 15 dias entre cada período para a readaptação dos animais à dieta de volumoso. As variáveis experimentais foram: ingestão de matéria seca (em kg, IMKG; % do peso vivo, IMPV; e metabólico, IMPM, respectivamente), flutuação da ingestão de matéria seca (FIMS) dos dias subseqüentes ao desafio com a dieta de concentrado e os parâmetros de fermentação ruminal (pH do líquido ruminal, lactato ruminal, concentração de ácidos graxos de cadeia curta, nitrogênio amoniacal e lactato ruminal). Não houve efeito de tratamento (P > 0.05) tanto para a ingestão de matéria seca quanto para a flutuação da ingestão de matéria seca. Os animais tratados com monensina apresentaram pH mais alto (P < 0.0001) que os demais tratamentos (MON = 6.06 vs. PAP = 5.89 e CTL = 5.91), independente de tempo. A concentração ruminal de lactato permaneceu baixa (0.23 mM), mesmo após o desafio com concentrado. A concentração de N-amoniacal do CTL foi menor (P = 0.0039), comparado à MON e PAP... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: This study was designed to evaluate the potential of the dry form of a multivalent polyclonal antibody preparation against several nutritional disturbs precursors ruminal bacteria (Streptococccus bovis, Fusobacterium necrophorum and Lactobacillus ssp.), as acidosis preventative feed additive to high concentrate fed cattle and as an alternative to monensin. It was used nine cannulated cows (677±98 kg of BW) allocated in a completely randomized desing with two periods of 20 d. Animals were separated in three treatments: control (CTL), multivalent polyclonal antibody preparation (PAP) and monensin sodium (MON). During the first five days of each period, animals were fed all forage diet. Ruminal acidosis was induced by an abrupt diet switch to a 74% concentrate diet during 15 d. An interval of 15 d was considered as ruminal washout in the meantime of the two periods, when animals were refed all forage diet to restablish normal ruminal pH conditions and cellulolitic microbial population. Ruminal acidosis evaluation parameters were: dry matter intake (kg/d, % of BW and % of BW0,75; DMIK, DMIB and DMIM respectivelly), dry matter intake fluctuations (DMIF) during the subsequent days after concentrate challenge, ruminal fermentation (pH; SCFAs, lactate and NH3-N concentrations). There were no treatment main effects (P > 0.05) for DMIK, DMIB, DMIM or DMIF. Higher pH was measured (P < 0.0001) in MON, compared to the other two treatments (MON = 6.06 vs. PAP = 5.89 and CTL = 5.91). Ruminal lactate concentration remained low (0.23 mM) throughout the entire experimental period. Ruminal ammoniacal-N concentration of CTL was lower (P = 0.0039), compared to MON and PAP (14.74 and 13.64 vs. 11.20 mg/dl, for MON, PAP and CTL, respectivelly). Molar concentration of acetate was not affected (P = 0.3288) by treatments. However, an interaction day x treatment (P = 0.0079) for propionate molar concentration was... (Complete abstract click electronic access below) / Orientador: Mário de Beni Arrigoni / Coorientador: Paulo Henrique Mazza Rodrigues / Banca: Jane M. Ezequiel / Banca: Paulo Roberto Meirelles / Banca: Carolina T. Marino / Banca: Paulo Roberto Lemes / Doutor

Graduation date: 2004

In the present study, the potential of low-melting point lipids, namely methyl palmitate (MP) and menhaden stearine (MS), were studied for delivery of water-soluble materials to fish larvae. Addition of the solid emulsifier, sorbitan monopalmitate (SMP) resulted in higher RE compared to the liquid emulsifier sorbitan sesquioleate (SSO). Additions of SMP were found to have a positive effect on the stability of lipid spray beads (LSB) at concentrations >10% (w/w) of lipid. LSB were shown to retain riboflavin with the highest RE when the lipid matrix was composed of a mixture of MP+10% SMP+1O% ethyl cellulose (w/w). Use of MP facilitated digestive breakdown of LSB by larvae of zebrafish, Brachydanio rerio, and glowlight tetra, Hemigrammus erythrozonus, as indicated by release of riboflavin from ingested LSB. LSB composed of MS performed better than LSB composed of MP when particulate glycine was incorporated within LSB. Highest retention efficiencies (RE) and delivery efficiencies (DE) were achieved by LSB composed of 100% MS. RE and DE of LSB were further improved when glycine was encapsulated as aqueous droplets rather than in a particulate form. The overall performance of LSB containing tyrosine showed that nutrients with similar water-solubilities to tyrosine can be very effectively delivered to early fish larvae. Visual observation indicated that LSB composed of 100% MS were broken down by larvae of clownfish, Amphiprion percula. Zein-bound particles (ZBP) were not efficient in delivering riboflavin to fish larvae due to high leaching rates. In an attempt to improve ZBP, we developed complex particles (CP) containing LSB incorporated in a dietary mixture bound by zein, to obtain a single particle type. The potential of LSB for delivery of free amino acids (FAA) was evaluated when LSB were incorporated within CP. RE and DE for tyrosine were significantly greater than those for alanine, glycine and serine. There was a significant inverse correlation between RE for FAA and their solubilities where FAA with low solubilites resulted in higher RE. Development of CP with high RE and DE for amino acids is an important step towards formulating a diet to allow early weaning of fish larvae onto artificial diets. / Graduation date: 2003

Thesis (doctoral)--Humboldt-Universität, Berlin, 2001. / Includes bibliographical references (p. 152-189).

No description available.

Six ruminally fistulated steers (average BW 317 kg) were used in a 5 X 5 + 1 Latin Square design to determine effects of humic/fulvic acid (HFA) on serum urea nitrogen (SUN), rumen pH, rumen ammonia nitrogen (RAN), and rumen VFA production in Holstein steers. Treatments included a control (0%), 0.5, 1.0 or 1.5% HFA, and a diet containing monensin (33 mg/kg). A quadratic feed intake response was observed; with intake lowest for 0.5 and 1.0 and highest for 1.5 relative to control steers. No treatment x time interaction was observed for RAN, pH, SUN, total VFA or individual VFA. No treatment differences were observed for total VFA concentrations (mM), or for molar proportion of acetate, propionate, butyrate or valerate. A quadratic response was observed for butyrate and isovalerate. However, HFA does not alter rumen fermentation in the same mode of action as monensin.

Zeolite (77% clinoptilolite) was supplemented in grower hog rations at a rate of 2 or 5%. The growth performance (weight gain, daily consumption and feed conversion) and air quality were compared against a control group's where zeolite was replaced by fine sand. A significant reduction in the feed/gain ratio and daily consumption was observed when 2% zeolite was fed to pigs weighing less than 40 kg. The same results were obtained when 5% zeolite was fed to pigs weighing more thoun 50 kg. No significant difference in air quality (CO 2, NH3, H2S and temperature) was noticed between the control and the zeolite room even if the NH3, level fell from 12.5 to 8.7 ppm when the zeolite level was increased from 2 to 5%. A slight reduction of odor intensity was observed in the zeolite room. In parallel with this research, a dynamic automated olfactometer for six lists was conceived and built according to American and European guidelines. This instrument measures agricultural odors with precision and speed.