M. Tech. (Department of Biotechnology, Faculty of Applied and Computer Sciences), Vaal University of Technology / Lipases have been one of the important biocatalysts that catalyse the transformation of lipids to yield very important products that can be of beneficial in food, agriculture, pharmaceutical medicine and for the biodiesel production. In the search for novel biocatalysts, notably lipases, the conventional culture-based techniques were used but it can only address sourcing the biomolecule from 1-10% of the microbial population leaving the wealth of the biomolecules packed in 90-99% of the microbial community unaccounted for. Metagenomic technique, which is culture-independent, was developed as a comprehensive approach to address literally 100% of the microbial population thereby maximizing the chances of obtaining novel biocatalysts with superior physico-chemical and catalytic traits. In principle, any biomolecule including lipase could be sourced from any biologically-active environment, of which animal rumen is one. However, among the rumenant animals goat has diverse feeding habit, thereby laying ground for increased microbial diversity in its gastro-intestinal tract. It was thus, postulated that goat rumen could be potential source of novel lipase isoforms. Therefore, the aim of the study was to extract metagenomic DNA from goat rumen and construct a metagenomic fosmid library and screen the library for lipase isoforms. The fosmid clones were functionally screened using 1% tributyrin as a substrate and five positive clones were selected. From the five clones, two fosmids were selected for further study. Following nucleotide sequencing and in-silico analysis of the insert of the two selected clones, one lipase encoding open reading frame (Lip-VUT3 and Lip-VUT5) from each fosmid clones of approximately 212 and 248 amino acids, respectively, was identified. The amino acid sequences of the Lip-VUT3 ORF contained a classical conserved lipase GSDL sequence motif while the amino acid sequences of the Lip-VUT5 ORF contained a classical G-L-S-L-G conserved lipase/esterase motif sequence. The two genes (Lip-VUT3 and Lip-VUT5) were successfully expressed in Escherichia coli BL21 (DE3) and the purified enzymes exhibited respective temperature optima of 60 °C and 70 °C, and respective pH optima of 6.0 and 10.0. Further biochemical characterisation indicated that Lip-VUT3 and Lip-VUT5 lipases showed tolerance towards a wide concentration (50%-100%) of methanol. Lip-VUT3 had a Km value of 0.287 mM while Lip-VUT5 had a Km value of 0.556 Mm. This shows that Lip-VUT3 lipase has a higher affinity for olive oil than Lip-VUT5. Lip-VUT3 and Lip-VUT5 were characterised to be true lipases that have been recovered from the rumen environment through metagenomic approach. Therefore, the study proved that metagenomic approach helps in recovering novel lipase isoforms with potential down stream industrial and therapeautic applications from goat rumen metagenome, a rich but untapped source.

No description available.

Raw milk sales are legal in 30 states, including Mississippi, where regulations are largely management-based and not food-safety related. The research objectives were to analyze the microbial profile of raw goat milk from Mississippi farms and assess food safety practices and perceptions of dairy goat farmers. Deficiencies and opportunities for improvement in raw goat milk safety were identified. Staphylococcus spp. was present in most (70%) milk samples but aligned with drying-off. E. coli, Enterobacteriaceae, and coliforms were observed in 4, 10, and 12 samples, respectively; no Salmonella spp. or Listeria monocytogenes were detected. The survey highlighted farmers' need for educational opportunities on safe milk handling with emphasis on handwashing. Most producers (80.8%) are willing to invest more in their farms, creating strategic opportunities for extension outreach to help with market expansion and sustainability. Overall, training accessibility could help producers nationwide by encouraging safe milk handling and best management practices.

Tesis por compendio / Goat milk is primarily destined for the production of fermented products, in particular cheese. Therefore, the control of antibiotic residues in milk is of great importance, since these could have negative repercussions on technological properties of the milk as well as on the health of consumers. In milk quality control programs, microbial inhibitor tests are widely applied to detect antibiotics during the screening stage. However, tests are non-specific and may be affected by substances other than antimicrobials which could inhibit the growth of the test micro-organism, causing false positive results. The aim of this thesis was to evaluate the interference, related to the presence of different contaminants in goat milk, on the response of microbial inhibitor tests commonly used in Spain to detect antibiotics (BRT MRL, Delvotest SP-NT MCS and Eclipse 100 tests). The influence of the physicochemical characteristics of goat milk on the false positive outcomes in microbial screening tests was also investigated. The suitability of microbial inhibitor tests for screening antibiotics in colostrum secretions was studied by analysing antibiotic-free colostrum and milk samples from forty-three Murciano-Granadina goats, collected every 12 hours during the first week post-partum. Microbial inhibitor tests were not suitable for the analysis of goat colostrum because they presented a high percentage of doubtful and positive results (up 37.2% in the 36 hours after partum). To evaluate the effect of caprine colostrum on the microbial test response, antimicrobial-free goat milk spiked with different concentrations of colostrum was analysed to calculate the inhibitory concentrations producing 5% of positive results. The highest interferences were obtained for the addition of colostrum from 12 to 24 hours post-partum and the colostrum concentrations producing 5% positive results were between 5.1 and 34.6%. The BRT MRL was the test the most affected. In another study, the interference of detergents and disinfectants used for the cleaning of milking equipment and milk storage tanks of dairy farms was investigated. Antimicrobial-free goat milk was spiked with eight concentrations of different cleaning products (5 acid, 5 alkaline, 5 domestic washing-up liquids, and 1 disinfectant) and analysed using microbial screening tests. The presence of acid detergent and disinfectant based on sodium hypochlorite in goat milk did not affect the microbial test response. However, alkaline detergents at concentrations ≥ 1 ml/l could lead to false positive results in microbial inhibitor tests (up to 16.7%) and from 4 ml/l on 100% positive results were obtained. Regarding the products used for home use, and those used on farms and small size dairies, washing-up liquid containing sodium laureth sulphate and ethanol had the greatest effects on microbial inhibitor tests, even starting from a relatively low concentration (1 ml/l). On the other hand, the presence of a relatively low concentration of detergents in goat milk (0.5 ml/l) slightly modified the detection capability of the microbial inhibitor tests for amoxicillin, ampicillin, benzylpenicillin, and cloxacillin, although the detection of these drugs at MRL (safe level) was not compromised. Antiparasitic agent residues in goat milk could be another possible cause of false positive results in microbial screening tests. An in vitro study to evaluate the effect of seven parasiticides commonly used in dairy goats was carried out. Further two studies, where albendazole and ivermectin were applied to two groups of dairy goats in lactation were performed. It should be noted that the parasiticide ivermectin is banned for the treatment of animals producing milk for human consumption, although its inclusion in this study was considered interesting to understand the potential effect of their residues in milk, in the event the practice was performed illegally. In the in vitro study, raw antibiotic-free milk from goats was spiked individually with eight different concentrations of albendazole, closantel, diclazuril, febendazole, levamisole, diazinon, and ivermectin. The microbial inhibitor test results showed a great variability according to the test and the drug under study. Of the tests considered, the BRT MRL test was the most sensitive to antiparasitic agents, with the lowest concentrations of antiparasitic agent causing 5, 10, and 50% of positive results. Generally, closantel and diazinon were the antiparasitic agents that produced higher interferences in all tests, since low concentrations already resulted in positive results, while only higher concentrations of diclazuril and ivermectin showed an inhibitory effect. To evaluate the effect of albendazole residues on the microbial inhibitor test response, eighteen healthy Murciano-Granadina goats in mid-lactation were treated with a single oral administration of the commercially available albendazole registered for dairy sheep (7.5 mg/kg b.w. of active compound) with a withdrawal period of 4 days for milk production in ovine. Albendazole and its metabolite residues in goat milk after under cascade treatment were not detected above MRL from the third day post-administration. However, a high occurrence of non-compliant results was obtained for the BRT MRL test during the first six days after treatment, suggesting that factors related to the albendazole application other than the drug concentration are able to affect the microbial inhibitor test response in some cases. Regarding the ivermectin study, twenty-eight Murciano-Granadina goats infested with Sarcoptes scabiei var. caprae were treated with a subcutaneous injection of ivermectin (200 μg/kg b.w.), with a second dose applied seven days after the first treatment. Drug residues in goat milk were recorded during the first fifteen days of the experiment with concentrations ranging from 8.13 to 24.25 ng/ml. In addition, all the microbial screening tests seem to be affected by the ivermectin treatment, with BRT MRL the most affected (20%) compared with Delvotest SP-NT MCS and Eclipse 100 (6.6 and 5.7%, respectively). These positive results cannot be associated with the ivermectin concentration in goat milk, as the concentrations measured were lower than the inhibitory concentrations as reported in a previous in vitro study for these microbial tests. Thus, as suggested by some authors, interferences could be related to changes or alterations caused by the application of the parasiticide agent or by the parasitic disease itself, which could affect the immune response of the animals favouring the presence of inhibitory substances in milk. The study of the effect of the goat milk composition on the specificity (rate of false positive results) of microbial inhibitor tests for screening antibiotics was also considered. Thus, individual goat milk samples (n=200) were analysed by microbial inhibitor tests using both visual and instrumental classification of the test results. The highest specificity values were obtained for the instrumental interpretation of the test results (94-99% vs 90-96%) due to the occurrence of samples with intermediate colorations (green-yellow, yellow-blue) making the visual classification more difficult and subjective. A relation was found between positive results in BRT MRL and Eclipse 100 tests and an elevated fat content in the goat milk. Positive outcomes in Eclipse 100 were associated with the butyric acid concentration in the milk. Further, the Delvotest SP-NT MCS test response was affected by elevated pH values, high lactoferrrin and myristoleic acid concentrations in the goat milk. This percentage of positive results could be minimized by a pre-treatment prior to microbial inhibitor test analysis, such as fat removal by centrifugation (3,100 g for 10 min at 4 ºC) and/or heating (80 ºC for 10 min). Undoubtedly, improvements on the specificity of the microbial inhibitor tests for screening antibiotics in goat milk are desirable to avoid the destruction of milk compliant for human due to the occurrence of false positive results. The related financial losses affect farmers and dairies. However, it should be noted that the presence of contaminants in goat milk could be avoided by applying good farming practices designed to ensure that milk is obtained from healthy animals under proper hygienic conditions so ensuring the food safety of goat milk and related dairy products. / Romero Rueda, T. (2015). Evaluation of false positive results in microbial inhibitor tests for screening antibiotics in goat milk [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/48552 / Compendio

Tesis por compendio / [ES] Los residuos de antibióticos en la leche constituyen un aspecto de gran importancia para la salud pública y pueden tener un efecto negativo en la industria láctea. Para proteger al consumidor se han establecido los Límites Máximos de Residuos (LMR) para diferentes antibióticos en la leche cruda. Sin embargo, la transferencia de estas sustancias de la leche al queso ha sido poco estudiada y, por lo tanto, se desconoce el impacto de la presencia de antibióticos sobre el proceso de elaboración y la seguridad del queso. El objetivo de la tesis ha sido evaluar la transferencia de los antibióticos más empleados en el ganado caprino lechero, desde la leche a quesos curados y frescos, así como estudiar el efecto sobre el proceso de fabricación y la calidad de los quesos durante la maduración. Para alcanzar el objetivo se han realizado elaboraciones de quesos curados (60 días) a partir de leche en presencia de diversos antibióticos (amoxicilina, bencilpenicilina, cloxacilina, eritromicina, ciprofloxacina, enrofloxacina y oxitetraciclina) a niveles admisibles (LMR) y fabricaciones de leche libre de antibiótico como referencia. Los resultados obtenidos sugieren que la mayor parte de los antibióticos en la leche no afectaron al proceso de fabricación del queso. Solamente la eritromicina y oxitetraciclina incrementaron el tiempo requerido en el proceso de elaboración. Respecto a las características del queso evaluadas a diferentes tiempos de maduración (0, 30 y 60 días), las pocas diferencias encontradas se refirieron a la concentración de ácidos grasos libres, el color y las propiedades de textura, pero en su mayoría no fueron detectadas en la evaluación sensorial. Sin embargo, cantidades variables de antibióticos, se transfirieron de la leche al queso (entre 7,4 y 68%). Las quinolonas y oxitetraciclina presentaron las más elevadas tasas de retención, así como persistencia a lo largo de la maduración, con altas concentraciones de quinolonas (enrofloxacina: 148±12 µg/kg; ciprofloxacina: 253±24 µg/kg) y de oxitetraciclina (20±5,7 µg/kg) después de los 60 días de curado. En el estudio de quesos frescos, se evaluó la presencia de residuos de medicamentos en la leche pasteurizada y en los quesos frescos a partir de leche de cabra con antibióticos (amoxicilina, bencilpenicilina, cloxacilina, neomicina, eritromicina, ciprofloxacina, enrofloxacina y oxitetraciclina) a niveles de seguridad (LMR). Los resultados mostraron que altas cantidades de antibióticos, entre el 71 y el 100% de la concentración inicial en la leche cruda, permanecieron en la leche pasteurizada y que fueron transferidas al queso en gran medida, con porcentajes de retención que oscilaron entre 37,5 y 75%. Con respecto a los márgenes de seguridad de estos productos, se calcularon teniendo en cuenta diferentes grupos de edades (niños, adolescentes y adultos), y los efectos negativos de estos antibióticos sobre la salud. Los resultados indicaron que el mínimo margen de seguridad en la leche pasteurizada lo presentaron la ciprofloxacina, enrofloxacina, y eritromicina para el grupo de niños. En relación al queso fresco, se obtuvo un elevado margen de seguridad para todos los antibióticos y grupos de edad considerados, lo que sugiere que este producto probablemente no tenga efectos negativos en la salud del consumidor. Es importante enfatizar que concentraciones relativamente altas de antibióticos podrían permanecer en la leche de cabra pasteurizada y productos relacionados, como los quesos frescos y de corta maduración. La presencia de estos antibióticos podría contribuir al desarrollo y propagación de la resistencia a los antimicrobianos que actualmente constituye un grave problema a nivel mundial. Los resultados de este trabajo podrían servir a las autoridades de salud pública para evaluar si los sistemas actuales de control de antibióticos en la leche y los productos lácteos son adecuados o deberían ser revisados. / [CA] Els residus d'antibiòtics en la llet animal constitueixen un aspecte de gran importància per a la salut pública, i poden tindre un efecte negatiu en la indústria làctia. Per a protegir al consumidor s'han establit els Límits Màxims de Residus (LMR) per a diferents medicaments veterinaris en la llet crua. No obstant això, la transferència d'estes substàncies de la llet al formatge ha sigut poc estudiada i, per tant, es desconeix el impacte de la presència de antibiòtics sobre el procés d'elaboració i la seguretat del formatge. L'objectiu de la tesi ha sigut avaluar la transferència dels antibiòtics més empleats en el bestiar caprí lleter, des de la llet a formatges curats i frescos, així com l'efecte sobre el procés de fabricació i la qualitat dels formatges durant la maduració. Per a aconseguir l'objectiu s'han realitzat elaboracions de formatges curats (60 dies) a partir de llet en presència de diversos antibiòtics (amoxicilina, bencilpenicilina, cloxacilina, eritromicina, ciprofloxacina, enrofloxacina i oxitetraciclina) a nivells admissibles (LMR) i fabricacions de llet lliure d'antibiòtic (control) com a referència. Els resultats obtinguts suggerixen que la major part dels antibiòtics en la llet no van afectar el procés de fabricació del formatge. Només l'eritromicina i l'oxitetraciclina van incrementar el temps requerit en el procés d'elaboració del formatge. Respecte a les característiques del formatge avaluades a diferents temps de maduració (0, 30 i 60 dies), les poques diferències trobades es van referir a la concentració d'àcids greixos lliures, el color i les propietats de textura, però majoritàriament no van ser detectades en l'avaluació sensorial. No obstant això, quantitats variables d'antibiòtics, es van transferir de la llet al formatge (entre 7,4 i 68%). Les quinolones i l'oxitetraciclina van presentar les més elevades taxes de retenció, així com persistència al llarg de la maduració, amb altes concentracions de quinolones (enrofloxacina: 148±12 µg/kg; ciprofloxacina: 253±24 µg/kg) i d'oxitetraciclina (20±5,7 µg / kg) després dels 60 dies de curació. En l'estudi de formatges frescos, es va avaluar la presència de residus de medicaments en la llet pasteuritzada i en els formatges frescos a partir de llet de cabra amb antibiòtics (amoxicilina, bencilpenicilina, cloxacilina, neomicina, eritromicina, ciprofloxacina, enrofloxacina i oxitetraciclina) a nivells de seguretat (LMR). Els resultats van mostrar que altes quantitats d'antibiòtics, entre el 71 i el 100% de la concentració inicial en la llet crua, van romandre en la llet pasteuritzada i que van ser transferides al formatge en gran manera, amb percentatges de retenció que van oscil·lar entre 37,5 i 75%. Respecte als marges de seguretat d'estos productes, es van calcular tenint en compte diferent grups d'edats (xiquets, adolescents i adults), i els efectes negatius d'estos antibiòtics sobre la salut. Els resultats van indicar que el mínim marge en la llet pasteuritzada ho van presentar la ciprofloxacina, la enrofloxacina, i l'eritromicina per al grup de xiquets. En relació al formatge fresc, es va obtindre un elevat marge de seguretat per a tots els antibiòtics i grups d'edat considerats, la qual cosa suggereix que este producte probablement no tinga efectes negatius en la salut del consumidor. És important emfatitzar que concentracions relativament altes d'antibiòtics podrien romandre en la llet de cabra pasteuritzada i productes relacionats, com els formatges frescos i de curta maduració. La presència d'estos antibiòtics podria contribuir al desenrotllament i propagació de la resistència als antimicrobians que actualment constitueix un greu problema a nivell mundial. Els resultats d'este treball podrien servir les autoritats de salut pública per a avaluar si els sistemes actuals de control d'antibiòtics en la llet i els productes lactis són adequats o haurien de ser revisats. / [EN] Antibiotic residues in milk are a great concern for public health, and they have negative implications for the dairy industry. To guarantee the safety of milk and derivates, Maximum Residues Limits (MRL) for different veterinary drugs in raw milk have been established. However, the transfer of these substances from milk to cheese, has been poorly studied and, therefore, the impact of the use of raw milk containing antibiotics on the cheese-making and the cheese safety is thus far unknown. The aim of this thesis was to evaluate the transfer of the most widely used antibiotics used in dairy goats, from milk to matured and fresh cheese, as well as their effect on the cheese-making process and the quality characteristics of the cheeses during ripening. To this end, antibiotic-free milk was spiked individually with seven veterinary drugs (amoxicillin, benzylpenicillin, cloxacillin, erythromycin, ciprofloxacin, enrofloxacin and oxytetracycline) and used to make mature Tronchón cheeses, which were analyzed at different ripening times (0, 30, and 60 days) to determine antibiotic residues, pH, chemical composition, proteolytic and lipolytic activities, color, and textural properties. The cheese-making process was unaffected by the presence of most antibiotics in milk. Only erythromycin and oxytetracycline significantly increased the time required for cheese production. Regarding cheese characteristics, the few differences found were related to the free fatty acid concentration, color and textural properties, which remained mostly undetected by the sensory analysis panelists. However, variable amounts of antibiotics, ranging from 7.4 to 68 %, were transferred from milk spiked with antibiotics, to cheese. Oxytetracycline and quinolones presented the highest retention rates as well as persistence along maturation, with high concentrations of quinolones (enrofloxacin: 148±12 µg/kg, ciprofloxacin: 253±24 µg/kg) and oxytetracycline residues (20±5.7 µg/kg) in cheeses after 60 days of ripening. In the study of fresh cheeses was evaluated the presence of drug residues in pasteurized fluid milk and fresh cheeses obtained from goat milk containing antibiotics (amoxicillin, benzylpenicillin, cloxacillin, neomycin, erythromycin, ciprofloxacin, enrofloxacin and oxytetracycline) at safety levels (MRLs). The safety margin of these dairy products for consumers was also evaluated. Results showed that high amounts of antibiotics, between 71-100% of the initial concentration in raw milk, remained in pasteurized goat milk and were transferred to cheese to a high extent, with retention percentages ranging from 37.5 to 75%. Regarding the safety margin of goat milk products, calculated taking into account different age groups (children, teenagers and adults), and the published negative effects of such antibiotics on consumer health, results indicate that the minimum safety margin of pasteurized milk was obtained for ciprofloxacin, enrofloxacin and erythromycin in the group of children. Regarding fresh cheese, an elevated safety margin was obtained for all antibiotics and age groups considered. It is important to emphasize that relatively high concentrations of antibiotics could remain in pasteurized fluid goat milk and related products such as fresh cheese and cheeses of a short ripening period. The presence of these antibiotics in dairy products might contribute to the development and spread of antimicrobial resistance, which is considered an important public health concern worldwide. The result of this research could serve the public health authorities to assess if current control systems of antibiotics in milk and dairy products are adequate or have to be revised. / Por último, quiero dar las gracias a la educación pública que permite que la economía no sea una barrera para la formación y al “Programa de ayudas a la investigación” (FPI-2014) de la Universitat Politècnica de Valencia, que me concedió la oportunidad de realizar está investigación durante los 4 años de trabajo. / Quintanilla Vázquez, PG. (2019). Effect of antibiotics in goat milk on the manufacture and characteristics of cheese [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/125701 / Compendio

No / Insight into the relative importance of sheep and goat herding and of the economic significance of each species (i.e., milk vs. meat vs. wool) in Medieval Greenland is obtained through the application of Halstead et al.¿s (2002) criteria for the identification of adult ovicaprine mandibles to faunal assemblages from three Norse farmsteads: Sandnes, V52a, and Ø71S. The economic strategies identified are broadly comparable between the two species and the Eastern and Western Settlement sites examined, and are suggestive of the subsistence production of meat and milk. Comparison with farmsteads elsewhere in Greenland indicates that socio-economic status and/or farmstead size interacted with geographical location in determining the economic strategies employed by the Norse farmers. A broader use of resources and a more varied diet are evident at larger farmsteads in Greenland and this paper suggests that such sites would have been better able than their smaller counterparts to withstand environmental deterioration during the early Middle Ages. These analyses have also confirmed that goats were relatively more common in Norse sites in Greenland than in Norse sites in Iceland, Orkney, or Shetland.

No / This research work was carried out to compare the physicochemical parameters of milk samples from four different animal species namely cow, goat, camel and sheep. Milk samples were collected from different areas of Misurata, Libya and analyzed for the key physiochemical parameters, pH, titratable acidity, total solids, ash, fat, protein and lactose. Furthermore in this study the concentrations of Zinc (Zn), Cadmium (Cd), Chromium (Cr), Magnesium (Mg), Manganese (Mn), Potassium (K), Calcium (Ca) Copper (Cu), Iron (Fe) and Lead (Pb) in similar commercial milk specimens from the same area were determined using microwave plasma- atomic emission spectrometry In fresh cow’s milk, the mean concentrations of Pb, Cd, Cr, Cu, Fe, Zn, Mg, Mn, Ca and K were 0.13± 0.19 (mg/l), 0.004± 0.001 (mg/l), 0.04± 0.01 (mg/l), 0.17± 0.11 (mg/l), 0.72± 0.02 (mg/l), 1.98± 0.04 (mg/l), 214.00± 0.20 (mg/l), 0.080± 0.05 (mg/l), 423.0± 3.5 (mg/l) and 427.0± 2.5 (mg/l), respectively. While the mean concentration of Pb, Cd, Cr, Cu, Fe, Zn, Mg, Mn, Ca and K, in the goat’s milk were 0.761 ± 0.78 (mg/l), 0.085 ± 0.02 (mg/l), 1.253 ± 0.18 (mg/l), 0.400± 0.08 (mg/l), 1.23± 0.21 (mg/l), 3.110± 0.15 (mg/l), 140.0± 0.31 (mg/l), 0.097± 0.07 (mg/l), 473± 5.12 (mg/l) and 510± 6.05 (mg/l), respectively. The concentration of Pb, Cd, Cr, Cu, Fe, Zn, Mg, Mn, Ca and K, in the camel’s milk were 0.025 ± 0.019 (mg/l), 0.091± 0.05 (mg/l), 0.069± 0.07 (mg/l), 0.080 ± 0.05 (mg/l), 1.680 ± 0.43 (mg/l), 5.380 ± 1.17 (mg/l), 120.0 ± 0.11 (mg/l), 0.094 ± 0.04 (mg/l), 520.0 ± 0.32 (mg/l) and 571.0± 0.81 (mg/l), respectively. The concentration of Pb, Cd, Cr, Cu, Fe, Zn, Mg, Mn, Ca and K, in the sheep’s milk were 0.062± 0.03, 0.106± 0.11, 0.040± 0.01, 0.201± 0.10, 0.880± 0.31, 5.350± 0.50, 180± 1.20, 0.072± 0.01, 478± 3.10, and 593.96± 1.87, respectively.

No description available.

MSCAGR (Animal Science) / Department of Animal Science / The Boer goat (Capra hircus) is one of the most desirable goat breeds for meat production. The impact of cryopreservation on the viability of its semen depends on the extenders, freezing and thawing methods. This study evaluated the effects on sperm viability in Boer goat semen extended using Bioxcell, Biladyl and Ham’s F10, and frozen in semen straws placed on a rack at 4, 5, 6 or 7 cm above the surface of liquid nitrogen. After storage in liquid nitrogen for 7 days, the frozen semen was thawed at 37 oC for 30 seconds or 90 oC for 5 seconds. Samples of sperm were also frozen to -196 oC in a programmable freezer, as the control regime for the freezing treatments. Sperm morphology, motility and viability were evaluated using the computer aided sperm analysis (CASA) system in a randomised design in which the treatments were in a 3 (extender) X 5 (freezing regime) and X 2 (thawing regime) factorial arrangement. The extenders Bioxcell and Biladyl were affected in the total motility, progressive motility and static (P<0.01), the motility was overall maintained only in straws placed at 5 cm above the liquid nitrogen level, with significant difference for the interaction extender X freezing regime in the total motility (p<0.01), non-progressive motility (p<0.05) and progressive motility (p<0.01), the 37 oC for 30 sec thawing regime had significantly more (P<0.05) in cut-head spermatozoa. Ham’s F10 extender had significantly lower normal spermatozoa (P<0.05) compare to Biladyl and Bioxcell extenders. In conclusion, the extender type, freezing and thawing regime were important factors for consideration in goat semen / NRF

Ce travail de thèse a pour but de fournir les bases scientifiques et techniques nécessaires au développement d'un programme de sélection en milieu tropical appliqué à une race caprine locale de Guadeloupe. La chèvre Créole est une chèvre de petite taille, aux bonnes aptitudes maternelles, issue du métissage de chèvres d'Afrique et d'Europe de l'ouest. Cette chèvre rustique est bien adaptée au climat tropical et présente une certaine tolérance aux parasites internes. Les éleveurs guadeloupéens l'utilisent pour la production de viande. En 2008, un projet de programme de sélection pour la chèvre Créole a démarré, projet qui réunit la coopérative caprine Cabricoop, la chambre d'agriculture et l'INRA. Les différentes étapes nécessaires à la conception et à l'optimisation de ce programme sont présentées dans ce travail de thèse. En termes d'objectif de sélection, des enquêtes auprès des éleveurs de la Cabricoop ont montré l'importance que les éleveurs attribuent tant à la croissance de leurs animaux qu'aux qualités maternelles des femelles. Afin de quantifier cette importance sur des bases économiques explicites, la modélisation des différentes composantes de la marge brute d'un atelier caprin a permis de déterminer les pondérations économiques des différents caractères à inclure dans l'objectif de sélection de la race. L'objectif de sélection intègre des caractères de production (poids et rendement carcasse à 11 mois), de reproduction (fertilité) et de résistance (OPG = nombre d'oeufs de strongles par gramme de fèces) et résilience (hématocrite) au parasitisme. Quel que soit le scénario envisagé en termes de quantité ou coût des intrants, le poids et la fertilité sont les deux composantes pour lesquelles une amélioration d'un écart type génétique de caractère amène le bénéfice escompté le plus grand. Les pondérations standardisées et cumulées de ces deux caractères expliquent entre 70 et 90% du total des pondérations économiques standardisées des caractères inclus dans l'objectif. A l'exception du rendement carcasse, les paramètres phénotypiques et génétiques des différents caractères inclus dans l'objectif de sélection ont été estimés pour la chèvre Créole à partir des données recueillies à l'unité expérimentale de Gardel. L'héritabilité est modérée pour le poids (0,32), faible pour la fertilité (0,11) et intermédiaire pour l'hématocrite (0,13) et l'OPG (0,18). Les corrélations génétiques estimées entre les caractères sont soit très faibles ou plutôt favorables. Les simulations de réponses à la sélection pour un noyau de sélection de 300 mères Créoles ont montré qu'il était possible d'améliorer à la fois le poids, le rendement carcasse, la fertilité, l'hématocrite et l'OPG. Améliorer résistance et résilience au parasitisme ne diminue que très légèrement la réponse à la sélection espérée sur les caractères de production. Il est donc possible de concilier des objectifs de production, de reproduction et d'adaptation au milieu pour la chèvre Créole en Guadeloupe. Ce travail de thèse a donc fourni les bases pour le développement d'un programme de sélection durable, pour une race locale, en milieu tropical. / This thesis aims at providing the scientific and technical basis needed for the settingup of a breeding programme applied to an indigenous guadeloupean breed of goat in the tropics.The local Creole breed of goat in Guadeloupe is a small-sized breed with good maternal qualities. This hardy breed comes from the natural mixing of breeds from Africa and Europe. It is well adapted to tropical climates and tolerates internal parasites. Guadeloupean farmers use Creole breed for meat production. Since 2008, the breeder's association Cabricoop, extension services and INRA collaborate to implement a breeding programme for Creole goat. This thesis presents the different steps needed for the design and optimisation of this programme. Concerning the breeding objective, a survey of Cabricoop farmers has shown the importance given to growth and maternal qualities in goats. In order to quantify this importance on sound economic basis, we modelled the components of the goat farm profit and derive the economic values of the different traits included in the breeding objective. We derived the economic values for production (body weight and dressing percentage at 11 months of age) and reproduction traits (fertility) as well as parasites resistance and resilience traits (FEC= number of worm eggs in the faeces and PCV= packed cell volume). Whatever the quantity or cost of input, the increase of one genetic standard deviation of body weight or fertility traits generated the highest profit. The standardised economic values of these traits explained 70 to 90% of the sum of the standardised economic values of all traits in the breeding objective. Genetic parameters of all traits except dressing percentage were derived for Creole goat. Heritability was moderate for body weight (0.32), low for fertility (0.11) and intermediate for PCV (0.13) and OPG (0.18). Genetic correlations were either low or favourable. Simulations of selection responses for a closed nucleus herd of 300 Creole does show that it is possible to improve weight, dressing percentage, fertility, PCV, and FEC simultaneously. Improving resistance and resilience to parasites decreases slightly the expected selection response on production traits without much trade-off. It is therefore possible to conciliate production, reproduction, and adaptation objectives for Creole goat in Guadeloupe. This thesis has provided the basis for the implementation of a sustainable breeding programme for a local breed in a tropical environment.