Research Articles (Animal Sciences)
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- ItemEffects of Saccharomyces cerevisiae, medium and forage type and their interactions on in vitro ruminal fermentation(Elsevier, 2020-09) Russouw, A.; Chevaux, E.; Chaucheyras-Durand, F.; Esposito, G.; Raffrenato, E.The objective of this study was to investigate the effects of a live yeast, Saccharomyces cerevisiae CNCM I-1077, at four doses (0, 1×105, 1×106 and 1 × 107 cfu/mL) according to the reducing medium used [Goering-Van Soest (GV), McDougall (MD) or Kansas State (KS)] on in vitro ruminal neutral detergent fibre digestibility (NDFd), rate of digestion of NDF (kd), organic matter digestibility (OMd), dry matter digestibility (DMd), pH as well as volatile fatty acids (VFA) concentration, using two forages (oat hay and wheat straw) with differing chemical composition. The maximum in vitro NDFd, DMd, OMd as well as kd were obtained with dose 1 × 106 cfu/mL, although differences between doses were not always significant. The pH estimates were the lowest with the 1 × 107 cfu/mL dose, but the differences were not all significant; however, 1 × 107 cfu/mL corresponded to significantly lower pH estimates compared to the control and 1×105 (6.51 vs. 6.60 and 6.59, respectively). The decrease in pH was accompanied by an increase in VFA concentrations as the yeast dose increased. The KS medium resulted in the lowest digestibility estimates, pH estimates as well as kd, regardless of yeast dose. The 1 × 106 cfu/mL was the better performing yeast dose in vitro resulting in higher digestibility estimates which indicates the yeasts ability to stimulate the microorganisms within the rumen by beneficially modifying rumen environment, thus promoting microbiota activity. The MD and GV media provide better environments for fermentation than the KS medium, resulting in higher in vitro NDFd, DMd, OMd, pH estimates as well as rate of NDF digestion. The MD and GV are also the media that resulted in more consistent results when analysing the effects of the live yeast. Our data suggest that the in vitro conditions have to be carefully chosen to be able to demonstrate rumen fermentation shifts with the use of live microbial additives.
- ItemUse of pawpaw (Carica papaya) seed in tilapia sex reversal(Reviews in Agricultural Science, 2020-10-18) Omeje, Victor Okonkwo; Lambrechts, Helet; Brink, DanieTilapia 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.
- ItemInclusion of Hermetia illucens larvae reared on fish offal to the diet of broiler quails : effect on immunity and caecal microbial populations(Czech Academy of Agricultural Sciences, 2020-05-30) Pasotto, Daniela; Van Emmenes, Liesel; Cullere, Marco; Giaccone, Valerio; Pieterse, Elsje; Hoffman, Louwrens Christiaan; Zotte, Antonella DalleHermetia illucens (black soldier fly, BSF) larvae meal has shown to be a good protein source in monogastric animal diets, but published data regarding its immunomodulatory properties is limited. For this purpose, a study has been conducted to evaluate the effects of larvae meal on selected immune parameters and caecal bacterial counts of broiler quails. Hermetia illucens larvae were reared on two substrates (100% chicken feed, BSF-M, or 50% chicken feed + 50% fish offal, BSF-F) in order to manipulate the fatty acid profile of larvae meal by increasing the long-chain omega-3 (n-3) polyunsaturated fatty acids which are known for their immunomodulatory properties. For immunological purposes, a total of 60 birds were randomly allocated to three dietary treatment groups (n = 20/treatment): control quail diet (CON), or quail diets including 10% of BSF-F or BSF-M larvae meal. Blood was collected 27 and 37 days after the trial commenced to determine the humoral immune response, serum lysozyme concentrations, serum bactericidal activity and protein fractions of the serum. The dietary inclusion of BSF-M meal resulted in an increased secondary humoral immune response compared to the CON treatment group (P < 0.01). Quails in the BSF-F treatment had significantly higher serum lysozyme activity compared to quails in the CON and BSF-M treatment group. Both larvae meals significantly increased cell-mediated immunity on day 37 (P < 0.001) but they had no effect on serum bactericidal activity. Both larvae meal sources resulted in higher α2-globulin levels on both sampling days, whereas γ-globulin levels were significantly lower in quails with the BSF-F treatment on day 27. Dietary treatments had no significant effect on caecal bacterial counts. In conclusion, the present study showed that the larvae meal had immunostimulatory effects in quails, but the rearing substrate of larvae strongly influenced the immunostimulatory properties of the larvae meal.
- ItemSericea lespedeza (Lespedeza juncea var. sericea) for sustainable small ruminant production : feed, helminth suppressant and meat preservation capabilities(Elsevier, 2020-10-10) Mahachi, Leo N.; Chikwanha, Obert C.; Katiyatiya, Chenaimoyo L. F.; Marufu, Munyaradzi C.; Aremu, Adeyemi O.; Mapiye, CletosSmall ruminants significantly contribute towards livelihood, food and nutrition security for people living in semiarid low-to-middle-income countries. However, their productivity is largely constrained by feed shortages, prevalence of gastrointestinal nematodes (GIN) and postharvest meat losses. The current review explores the possibility of using sericea lespedeza (Lespedeza juncea var. sericea) as a natural helminth suppressant, feed ingredient and meat preservative for improving small ruminant health, meat production and shelf life. Sericea lespedeza has moderate contents of crude protein, fibre, minerals, vitamins, amino acids, and diverse composition of physiologically active substances such as condensed tannins, sterols and flavanols from which it derives nutritional, anti-bloat, helminth suppressant, antimicrobial and antioxidative properties. Overall, the present review demonstrates the potential of feeding sericea lespedeza to small ruminants as a sustainable means of controlling GIN and enhancing meat production and shelf life, while also reducing greenhouse gas (GHG) emissions. However, more research is required to determine optimal feeding strategies and doses for reducing GHG emissions while improving health, meat production and quality of small ruminants.
- ItemEffect of pawpaw (Carica papaya) seed meal on sex determination, growth, and survival, of Oreochromis mossambicus fry(AquacultureHub Inc, 2018) Omeje, Victor Okonkwo; Lambrechts, Helet; Brink, DanielThe production of monosex tilapia populations is a potential and effective solution for the precocious breeding and indiscriminate spawning that occurs in mixed sex culture systems. This study investigated the possibility of using Carica papaya seed meal (PSM) to skew the sex ratio of sexually undifferentiated Oreochromis mossambicus fry. A total of 2160 fry were used in the study, and fish were allocated to 12 treatment groups in triplicate, with 60 fish per replicate. The experimental diets fed included a basal diet (BD), 60mg methyl testosterone/kg BD, and 5 treatment diets containing 10, 15, 20, 25 and 30g PSM/kg of the BD, respectively for 30 and 120 days. PSM was able to skew the sex ratio in favor of males, with the proportion of males to females increasing with an increase in PSM content of the diet. The highest percentage phenotypic males (77.8%) induced by the PSM was obtained among the groups that received 20g and 30g PSM/kg BD. The growth and survival rates of the fish were not influenced by any of the treatment diets. Fragmentation of ovarian nuclei, hypertrophy of interstitial cells, and vacuolization of hepatocytes were observed in the gonads and hepatic tissues. The study demonstrated that an inclusion level of 20g PSM/kg BD was effective in converting females to phenotypic males.