Impact of dietary incorporation of Spirulina (Arthrospira platensis) and exogenous enzymes on broiler performance, carcass traits and meat quality

This study assessed the effect of Spirulina (Arthrospira platensis), individually and in combination with exogenous enzymes, on growth performance, carcass traits, and meat quality of broiler chickens. One hundred and twenty Ross 308 male chickens were allocated into 40 battery brooders, with 3 birds per cage, and fed ad libitum a corn-based diet during the first 21 D of the trial. The experimental period lasted from day 21 to 35, during which birds were fed 4 different diets: a corn-soybean basal diet, taken as the control group, a basal diet containing 15% Spirulina (MA), a basal diet containing 15% Spirulina plus 0.005% Rovabio Excel AP (MAR), and a basal diet containing 15% Spirulina plus 0.01% lysozyme (MAL). Body weight gain (P , 0.001) and feed conversion rate (P , 0.001) were improved in control chickens, when compared with those fed with Spirulina. In addition, Spirulina increased the length of duodenum plus jejunum in relation to the other treatment (P , 0.01). Chickens on the MAL diet showed a considerable increase in digesta viscosity (P , 0.05) compared with the control group. Breast and thigh meats from chickens fed with Spirulina, with or without the addition of exogenous enzymes, had higher values of yellowness (b*) (P , 0.001), total carotenoids (P , 0.001), and saturated fatty acids (P , 0.001), whereas n-3 polyunsaturated fatty acid (P , 0.01) and a-tocopherol (P , 0.001) decreased, when compared with the control. In conclusion, the incorporation of 15% Spirulina in broiler diets, individually or combined with exogenous enzymes, reduced birds’ performance through a higher digesta viscosity, which is likely associated with the gelation of microalga indigestible proteins. In addition, cell wall of Spirulina was successfully broken by the addition of lysozyme, but not by Rovabio Excel AP. Therefore, we anticipate that the combination of lysozyme with an exogenous specific peptidase could improve the digestibility of proteins from this microalga and avoid their detrimental gelationinfo:eu-repo/semantics/publishedVersio

Strategy of Utilization of Locally Available Crop Residues and By-Products for Livestock Feeding in Tunisia

Important quantities of crop residues and by-products are yearly available in North African countries. This paper presents the screening of the most important by-products in Tunisia, their nutritional characteristics and the appropriate strategies to use most of them in order to improve ruminants feeding systems. One or several by-products are specifie of each region of the country but most of them are localized in the northern region. Some of the agricultural wastes are available in important quantities but are of nutritionally poor or moderate qualities (straw, olive wastes, poultry litter, etc), while others are produced in limited amounts but are of very interesting feeding values (sugar beet pulp, brewers grain, date residue, etc). The main applied strategies to valorize Tunisian agricultural by-products consist in ammoniation of cereal straws along with supplementation with multinutriment blocks and formulation of balanced diets based totally or partially on them. These alternatives are crucial in the improvement of feeding values of studied diets and animal performances essentially by improving micro-bial activity in the rumen. In Tunisia such solution could be applied both in extensive and moderate animal production systems

Influence of dietary replacement of sunflower oil with milk thistle (Silybum marianum) oil on chicken meat quality and antioxidant status of liver

The research focused on the effects of dietary replacement of 3% sunflower oil (SO group) with 3% milk thistle oil (MTO group) on the technological quality of meat, such as pH value, colour (CIE L*, CIE a*, CIE b*), drip loss (%), shear force (N), and cooking loss (%), as well as on the content of fatty acid lipids in broiler breast and thigh muscles. Significant difference (P < 0.05) was determined for pHi, pHu, CIE a*, CIE b* values between groups, although the values for the stated indicators were within the standard range. Lipids of breast meat of the MTO group contained more arachidic acid (P < 0.001), octadecenoic acid isomer B (P = 0.047) and eicosatrienoic acid (P = 0.041), and less α-linolenic acid (P < 0.001) and Σn-3PUFA. Lipids of thigh meat of the MTO group contained more ΣSFA, myristoleic acid, eicosatrienoic acid (P < 0.05) and eicosenoic acid (P < 0.001), and less α-linolenic acid, and had narrower Σn-3/n-6 PUFA ratio than the SO group. According to the antioxidant status of broiler liver, there was significantly higher catalase activity determined in the MTO group