The effect of cryopreservation on the survivability, viability and motility of Merino (Ovis aries) and African buffalo (Syncerus caffer) spermatozoa

Thesis (M. Sc. Agric.) -- University of Stellenbosch, 1996.One copy microfiche.Full text to be digitised and attached to bibliographic record

Influence of extending the pre-slaughter interval after second vaccination on the carcass cutting yield and the quality of meat from immunocastrated lambs

The influence of extending the vaccination-to-slaughter interval of immunocastrated lambs on carcass cutting yield and meat quality of the Longissimus thoracis (LT) muscle was investigated in forty Dohne Merino lambs (8.5 months old; 53.7 ± 4.8 kg). Immunocastration booster vaccination intervals of six (IC6; n = 10) and four (IC4; n = 10) weeks prior to the slaughter age were used, with two weeks between primary and secondary vaccinations. A further 10 lambs were Burdizzo-castrated at 6.5 months old (B). The control treatment remained intact (R; n = 10). Prime cutting yields, LT muscle area, LT subcutaneous fat thickness and instrumental meat quality were accessed. Both castration methods increased LT fat thickness and decreased meat CIE a* (redness) values. Extending the vaccination-to-slaughter interval of immunocastrates increased the gastrointestinal tract fat and decreased meat redness. Immunocastration of male lambs can thus be used to manipulate backfat without negatively influencing carcass weight, cutting yield or meat quality

Hormonal profile and reproductive parameters of pre-vitellogenic mozambique tilapia (oreochromis mossambicus) on pawpaw (carica papaya) seed meal

CITATION: Omeje, V. O., Lambrechts, H. & Brink, D. 2019. Hormonal profile and reproductive parameters of pre-vitellogenic mozambique tilapia (oreochromis mossambicus) on pawpaw (carica papaya) seed meal. Journal of Agricultural Science, 11(2):524-532, doi:10.5539/jas.v11n2p524.The original publication is available at https://www.ccsenet.org/journal/index.php/jasThe use of phytochemicals to control precocious maturation and indiscriminate spawning among tilapia species is an important issue in aquaculture. This study investigated the influence of pawpaw (Carica papaya) seed meal on the reproductive performance, and the sex hormone profile of sexually immature Mozambique tilapia (Oreochromis mossambicus). Pawpaw seed meal (PSM) were included in a tilapia commercial diet (basal diet) at an inclusion level of 0 PSM, 10 PSM and 30 PSM g/kg of the basal diet (BD), respectively, and fed to immature O. mossambicus for a period of 30 and 60 days, respectively. Enzyme-linked immune-sorbent assay (ELISA) procedures were used to quantify the plasma levels of 17β-estradiol and 11-ketotestosterone. The inclusion of PSM did not affect the growth and survival rate of the O. mossambicus. The plasma levels of 11-ketotestosterone did not differ among the treatment groups. The 17β-estradiol levels of female fish that received 30 PSM g/kg BD for 60 days were significantly lower (p < 0.05) than the levels reported for females that were not fed the PSM. In females, the PSM reduced the gonad weight, GSI, fecundity and egg diameter of fish. The study concludes that pawpaw seed meal affected the reproductive function of the female O. mossambicus though the changes were reversible.https://www.ccsenet.org/journal/index.php/jas/article/view/0/38127Publisher's versio

A Descriptive Study on the Carcass, Muscle, and Offal Yields of the Plains Zebra (<i>Equus quagga</i>) Harvested in Two Seasons

This study presents descriptive data on the meat and offal production of Plains zebras harvested in the winter (n = 8) and summer (n = 12) seasons, at different respective locations in the Western Cape Province of South Africa. The cold dressing percentages were numerically higher for the winter (58.0 ± 0.60%) than for the summer-harvested animals (56.60 ± 0.70%). Heavier internal offal yields were reported for the winter-harvested group (70.76 ± 21.8 kg) compared to the summer-harvested animals (66.13 ± 3.78 kg). As harvest season had no influence, pooled data of the percentage contribution of each muscle to cold carcass weight indicated that the Longissimus et lumborum (3.5 ± 0.18%), semimembranosus (1.6 ± 0.04%), biceps femoris (2.7 ± 0.05%) and semitendinosus (0.9 ± 0.02%) muscles differed significantly in their respective contributions to cold carcass weight. No significant differences were recorded between the contribution of the infraspinatus (0.6 ± 0.02%), supraspinatus (0.4 ± 0.03%) and psoas major (0.6 ± 0.02%) muscles. Carcass and muscle yields, as well as low-cost protein offal yields from this study indicate that the Plains zebra has the potential to be used and distributed as an alternative protein source

Hepatic and haemato-biochemical alterations in juvenile Mozambique tilapia (oreochromis mossambicus) on pawpaw (carica papaya) seed meal

CITATION: Omeje, V., Lambrechts, H. & Brink, D. 2019. Hepatic and haemato-biochemical alterations in juvenile Mozambique tilapia (oreochromis mossambicus) on pawpaw (carica papaya) seed meal. Journal of Agricultural Science, 11(8):20-30, doi:10.5539/jas.v11n8p20.The original publication is available at https://www.ccsenet.org/journal/index.php/jasPawpaw seed meal (PSM) can be used as an antifertility agent in animals, however there is no information on its potential toxicological effect on Mozambique tilapia (O. mossambicus). In this study the effect of PSM on the liver, blood haematological and biochemical parameters of O. mossambicus juveniles was assessed to ascertain its suitability as a reproductive suppressant. The PSM was administered at an inclusion level of 10 g and 30 g/kg of a commercial tilapia diet (basal diet, BD) for 30 and 60 days, respectively. The potential toxicological effect was assessed by determining the extent of change in the normal haematological (RBC count, haematocrit, haemoglobin, MCV, MCH, MCHC, thrombocyte count, absolute WBC and differential cell counts) and biochemical (cholesterol, total protein, albumin, globulin and glucose) parameters. Haematological and biochemical profiles of different treatment groups did not differ throughout the course of the investigation. Liver weight and hepatosomatic index values of the treated fish were comparable to those of the control. The absence of any effect of the blood parameters measured in this study also indicate that PSM has no compromising influence on the immune system of the fish, indicating that PSM can be considered as a safe alternative to induce masculinization in Mozambique tilapia, and therefore act as a reproductive inhibitor.https://ccsenet.org/journal/index.php/jas/article/view/0/39662Publisher's versio

Use of pawpaw (Carica papaya) seed in tilapia sex reversal

CITATION: Omeje, V. O., Lambrechts, H. & Brink, D. 2020. Use of pawpaw (Carica papaya) seed in tilapia sex reversal. Reviews in Agricultural Science, 8:230–242, 2020, doi:10.7831/ras.8.0_230.The original publication is available at https://www.jstage.jst.go.jpTilapia breeds effortlessly in captivity, with this attribute which is considered as the “Achilles heel” of the species, because it predisposes pond systems to overcrowding and low weight at harvest. Efforts to mitigate this shortcoming include mono-sex culture using exogenous hormone to reverse the sex of sexually undifferentiated fish. This is premised on the fact that improvement in the growth by mono-sex culture will lead to shortened production times and a more uniform weight at harvest, which will ultimately benefit the producers. However, the use of exogenous hormones in aquaculture has recently raised concerns about the effect on farm workers, consumers and on the environment. Recently research has focused on the use of substances of plants origin which mimic the action of hormones as a potential approach to achieve sex reversal in fish. Pawpaw (Carica papaya) seed contains phytochemicals that hold great promise as a sex reversal and a reproductive inhibition agent in aquaculture. The purpose of this study was to conduct a systematic review of the relevant literature on the possibility of using a less harmful phytochemicals abundant in the plant to effect sex reversal of sexually undifferentiated tilapia.Publisher's versio

Analysis of Oleanolic Acid and Ursolic Acid, Potential Antifertility Agents in Moringa (\u3cem\u3eMoringa oleifera\u3c/em\u3e) Seed

Oleanolic acid (OA) and ursolic acid (UA) are isomeric triterpenes that are difficult to separate chromatographically. Studies have indicated that both OA and UA have antifertility properties in several livestock species, suppressing attainment of puberty, gonad function and gamete production. Being able to determine the presence and quantity of the OA and UA in moringa and pawpaw seeds will allow for calculation of optimal inclusion levels of these acids in animal diets forantifertility-activity. The purpose of the study was thus to quantify the levels of OA and UA in Moringa and pawpaw seed powder by means of ultra-high performance liquid chromatography with electrospray ionization tandem mass spectrometry (UHPLC-ESI-MS/MS). Only OA was detected in moringa seeds at a concentration level of 0.508 µg/g ± 0.032 µg/g dry weight. UA and OA could not be detected in pawpaw seeds used in this study. The presence of OA in moringa seeds suggest that the seeds can be included in tilapia diets as a potential antifertility treatment to control precocious breeding in tilapia culture in small scale farming systems in Sub-Saharan Africa. Further studies are warranted to determine the levels of OA and UA composition in moringa seeds from other parts of the Sub-Saharan Africa (other than Zambia)

Combined effect of dietary protein, ractopamine, and immunocastration on boar taint compounds, and using testicle parameters as an indicator of success

CITATION: Needham, T. et al. 2020. Combined effect of dietary protein, ractopamine, and immunocastration on boar taint compounds, and using testicle parameters as an indicator of success. Foods, 9(11):1665, doi:10.3390/foods9111665.The original publication is available at https://www.mdpi.comThis study investigates the combined effect of immunocastration, dietary protein level (low, medium or high) and ractopamine hydrochloride supplementation (0 or 10 mg/kg) on the adipose concentrations of androstenone, skatole and indole in pigs, and explores whether body mass, carcass fatness or testicular parameters may be indicators of boar taint in these carcasses. Immunocastration was successful in decreasing testicle functioning, and adipose androstenone and skatole concentrations, in all individuals. Immunocastration decreased testicle weight and length, seminiferous tubule circumference and epithelium thickness. Testicle tissue from immunocastrates was also paler, and less red in color, in comparison to non-castrated controls. Dietary protein level and ractopamine hydrochloride supplementation had no influence on the adipose concentration of androstenone, skatole and indole. Testicle size and color were moderate to strong indicators of androstenone and skatole concentrations in the carcasses, and thus vaccination success. Immunocastration together with the adjustment of dietary protein and ractopamine hydrochloride supplementation, is successful in preventing boar taint while maintaining growth performance.South African Pork Producers’ OrganisationSouth African Research Chairs in Meat Science Initiativehttps://www.mdpi.com/2304-8158/9/11/1665Publisher's versio