Browsing by Author "Van Emmenes, Liesel"

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    Evaluation of phytase enzymes on performance, bone mineralisation, carcass characteristics and small intestinal morphology of broilers fed maize soya bean diets
    (Stellenbosch : Stellenbosch University, 2014-04) Van Emmenes, Liesel; Pieterse, E.; Hoffman, Louwrens C.; Stellenbosch University. Faculty of AgriScience. Dept. of Animal Sciences.
    ENGLISH ABSTRACT: The use of phytase enzymes to liberate phosphorus and other phytate bound nutrients in monogastric animal diets are becoming common practice and several commercial phytase enzymes are available on the market. Phytase manufacturers supply nutritionists with matrix values for the specific phytase, enabling nutritionists to effectively decrease the dietary concentrations of phosphorus and nutrients during diet formulation. A 32 day experiment was conducted with 5120 broiler chicks fed diets supplemented with different commercial phytase enzymes (1000 FYT or 1500 FYT HiPhos/kg diet, 1500 FYT Ronozyme/kg diet, 500 FTU Natuphos/kg diet or 500 FTU Phyzyme/kg diet) at levels recommended by the manufacturers and with similar phosphorus equivalence. The nutrient content of the diets supplemented with 500 FTU Natuphos, 500 FTU Phyzyme 1500 Ronozyme and 1000 FYT HiPhos were reduced according to the matrix values of 1000 FYT/kg HiPhos, whilst the diet supplemented with 1500 FYT HiPhos /kg diet was reduced according to the matrix values 1500 FYT HiPhos. The objectives of this study were threefold: (i) to confirm the matrix value for a newly developed phytase (HiPhos, DSM Nutritional Products, Basel, Switzerland), at two different inclusion levels, using weight gain and bone parameters of broilers as response criteria; (ii) to compare production and bone parameters of broilers reared on three different commercial phytases to broilers reared on HiPhos (iii) to investigate the effect that supplementation of these four phytases has on water intake, carcass characteristics, organ weights and gastrointestinal tract morphology of broilers. The matrix values for 1500 FYT HiPhos were confirmed by using live weight gain as response criteria, but results for bone parameters were insufficient in confirming the matrix values. The matrix values for 1000 FYT HiPhos were confirmed by the results for tibia weight and tibia strength, but results for weight gain were insufficient to confirm the values. The matrix values for 1000 FYT HiPhos and 1500 FYT HiPhos could not be confirmed nor disproved, nevertheless results from the current trial proved diets supplemented with HiPhos to be more economically viable when compared to the standard commercial broiler diet. Total feed and water intake were not influenced by phytase supplementation. Production parameters (live weight, feed intake, feed conversion ratio, European production efficiency factor and average daily gain) and bone parameters (tibia strength, fat free tibia weight, fat free tibia ash and mineral content) did not differ between phytase treatments and therefore all the commercial phytases were equally effective to the HiPhos phytase. Furthermore, results indicate that the investigated phytases had no effect on internal organ weight or gastrointestinal tract morphology in broilers. Overall the results obtained from the study indicate that the use of phytase as feed additive has no negative effects on growth performance, carcass characteristics or bone parameters. No major differences for the production and bone parameters were observed between broilers supplemented with different phytases. Therefore the costs of these phytases can be the determining factor when nutritionists decide which commercial phytase to use.
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    Exploring the potential health benefits from Hermetia illucens and Chrysomya chloropyga larvae meal in poultry diets
    (Stellenbosch : Stellenbosch University, 2021-04) Van Emmenes, Liesel; Pieterse, Elsje; Hoffman, Louwrens C.; Stellenbosch University. Faculty of AgriSciences. Dept. of Animal Sciences.
    ENGLISH ABSTRACT: The unaffordability and scarcity of good quality protein sources are especially severe for small scale farmers in rural areas of Africa. For this reason, the monogastric animal feed industry is in urgent need of new and sustainable protein sources. Insects have been proposed as a sustainable, high-quality protein source. A major focus has been placed on Hermetia illucens (BSF) (Diptera: Stratiomyidae) larvae due to their ability to break down organic matter from waste streams and convert it into high-quality protein. However, research on carrion species such as Chrysomya chloropyga (CC) (Diptera: Calliphoridae) larvae, which are excellent in converting animal offal, is scarce. Even though numerous trials have proven that larvae meal can be used as a protein source in monogastric animal diets, the following question remains: Is this novel protein source only good to use as a protein source in animal diets to sustain production, or does it hold other benefits? Since published data regarding the immunomodulatory and antimicrobial properties of larvae meal in poultry diets are limited, this study focused on the effects of BSF and CC larvae meals on some of these properties when used in the diets of broiler chickens and broiler quails. The larvae meal sources used in this study provided essential amino acid profiles close to the requirements of broilers. Larvae meal from both Diptera species was accepted by broilers when used in a diet preference trial. Three animal trials were conducted for this study to determine the immunomodulatory and antimicrobial properties of larvae meal. In the first trial, BSF and CC larvae meals were used in the diets of 108 broiler female chickens over a 35-day growth period. Larvae meal was added to the diets at inclusion levels of 10% and 15%. Results were compared with broilers receiving a maize-soya-fishmeal based control diet (CON) or a control diet supplemented with an antimicrobial growth promoter, Zinc Bacitracin (ZincBac). The weekly measured production parameters for all treatment groups were similar to that of the control group, except for broilers in the 15%BSF group which had a poorer feed conversion ratio (FCR) at 35 days of age. Broilers were injected with sheep red blood cells and phytohaemagglutinin-P (PHA-P) to determine the effect of dietary treatments on the humoral immune response and cell-mediated immune response in the form T-cell lymphoproliferation. Increased antibody titers against sheep red blood cells and a greater swelling response to PHA-P were detected in broilers receiving BSF and CC larvae meal sources. Treatments had no negative effects on haematological parameters, lymphoid organ weights, liver colour, or gastrointestinal pH. Based on these results, it was concluded that the BSF and CC larvae meals were non-toxic and had no negative effect on the physiological status of the broiler chickens. For the second trial, BSF larvae were reared on two different substrates: 100% commercial layer chicken mash (BSF-M), or 50% commercial layer chicken mash + 50% fish offal (BSF-F). Resulting larvae were used as feed for quail. This trial aimed to determine the effects of larvae meal on specific immune parameters and selected bacterial counts in the quail ceca. Fish offal was chosen to form part of the larvae’s substrate to increase the content of long-chain omega-3 (n-3) fatty acids in the larvae meal. Sixty quails were injected with porcine red blood cells, and PHA-P. Quails in the BSF-F group exhibited lower slaughter weight compared to quails in the CON and BSF-M group. Quails in the BSF-M group had a significantly higher secondary humoral immune response compared to the CON group. Dietary inclusion of larvae meal significantly increased lymphoproliferative response, with the BSF-F group exhibiting the greatest response. Dietary treatments had no effect on in vivo serum bactericidal activity against E. coli. Most serum protein fractions were not influenced by treatment, with the exception of α2-globulin being higher in the BSF-M and BSF-F groups, whereas γ-globulin concentrations were lower in the serum of the BSF-F group. It was concluded that larvae meal has immunomodulatory properties in broiler quails, but the substrate used to rear the larvae can influence the results. In a third trial, a challenge experiment with Salmonella enterica serovar Enteritidis A9 was conducted. A total of 476 broiler chickens were orally challenged with Salmonella Enteritidis. Broilers received either a control diet (CON+SAL), control diet supplemented with oxytetracycline antibiotic growth promoter (ANTIBIO+SAL), a diet containing 10% CC larvae meal (CC+SAL) or 10% BSF larvae meal (BSF+SAL). One group of broilers received the control diet but was not infected with Salmonella and served as the negative control group (CON-NEG). One bird per cage (replicate) was slaughtered on day 11, 14, 21, 24 and 28 for ceca and blood collection. Feed conversion ratio of chickens in the CC+SAL, BSF+SAL and ANTIBIO+SAL treatment groups were significantly improved compared to the CON+SAL treatment group. Since FCR were similar between broilers receiving larvae meal and broilers receiving the antimicrobial growth promoter, it is possible that 10% larvae meal can replace the need for antibiotic growth promoters in broiler diets since it delivered similar results in challenged animals. Oxytetracycline significantly reduced Salmonella colonisation one- and four-days post-infection, but ceca Salmonella levels slowly increased again over time in this treatment group. The opposite was noticed for the CC+SAL group, with CFU per ceca counts slowly decreasing until being significantly lower than the CON+SAL group on day 28. Salmonella counts were similar in the BSF+SAL and CON+SAL groups on all the slaughter days. Both larvae meal sources significantly enhanced serum bactericidal activity against Salmonella when compared to the CON+SAL group. Lymphoproliferative response to the PHA-P test was significantly higher in the CC+SAL, BSF+SAL and ANTIBIO+SAL treatment groups; whereas only the BSF+SAL group had enhanced lysozyme concentrations in their blood shortly after infection occurred. Lastly, treatments had no effect on lymphoid organ weight, haematological parameters, or serum interferon-gamma (IFN- γ) levels of broilers. To summarise the results from the three trials; BSF and CC larvae meals showed promising immunostimulating properties in broiler chickens and quails - dietary larvae meal showed signs of an increased humoral immune response, T lymphocyte function and serum lysozyme activity in both animal species. Even though BSF larvae meal did not change cecal microbial composition against selected bacterial counts in quails, when challenged with Salmonella Enteritidis, dietary CC larvae meal exhibited antimicrobial properties by decreasing Salmonella colonisation in the ceca as well as increasing serum bactericidal activity against the challenged organism. Even though no difference in FCR was observed in this study when healthy broilers or quails received larvae meal, there was an indication that larvae meal could improve FCR in infected animals, since BSF and CC larvae meal improved FCR in Salmonella infected broilers. To conclude, all the immune parameters studied in these trials were either improved or similar for poultry receiving dietary larvae meal, but the larvae species, as well as the substrate used to rear the larvae on, may affect the response.
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    Hermetia illucens Larvae Reared on different substrates in broiler quail diets : effect on physicochemical and sensory quality of the quail meat
    (MDPI, 2019-08-02) Cullere, Marco; Woods, Michael Josias; Van Emmenes, Liesel; Pieterse, Elsje; Homan, Louwrens Christiaan; Zotte, Antonella Dalle
    This research aimed at improving the fatty acid (FA) profile of Hermetia illucens larvae (HI) and evaluating the effects of their inclusion in growing broiler quails’ diets on the meat physicochemical quality, including detailed amino acid (AA) and FA profiles, sensory traits, and retail display. HI larvae were reared on two different substrates: layer mash (HI1) and 50:50 layer mash/fish offal (HI2). A total of 300 10-day-old quails were allocated to the three dietary groups (five replicates/each): a soybean meal-based diet was formulated (Control), and two other diets were formulated that included either 10% HI1 or HI2. Quails were fed the experimental diets until slaughter. Diets were formulated to be isonitrogenous and isoenergetic. Breast meat quality was affected by the dietary treatments, which displayed different proximate compositions and AA and FA profiles. Meat physical quality, sensory profile, and retail display remained unaffected for the most part. Overall, results showed that it is possible to improve the FA profile of the HI-fed quails’ meat and thus lipid quality through substrate modulation of the HI’s diet.
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    Inclusion 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 Dalle
    Hermetia 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.