| dc.description.abstract | The demand for slaughter practices to be carried out under conditions of welfare, and that guarantee quality meat products, is growing among consumers. In Mexico, diverse methods for stunning rabbits before slaughter are available. However. such methods have been poorly evaluated, since rabbit farming takes place mainly in small-scale production units. The present study was based in a sample of 120 California rabbits, including both sexes, with an average weight of 2 kg and 65 days of age. Electrical stunning and manual stunning method were used before slaughter. Three objectives were determined in the form of chapters. Chap.1. Objective: To relate the effect of two stunning methods and gender by evaluating the manifested conducts, lesions in the carcass and the factors that contribute to animal welfare (AW) during stunning and slaughter. A completely randomized 2x2 factorial design was used, risk factors for the lesions were obtained and the conducts were compared with a Mann-Whitney test and Kruskall Wallis test. Results indicate that electrical stunning before slaughter resulted in better AW conditions than manual stunning. Chap.2. Objective: To compare the effect of two stunning methods for rabbits in the characteristics of the carcass, as well as in the chemical and physical properties of the meat. Live-weight, warm-carcass weight and cold-carcass weight were registered; pH (1, 24 and 48h postmortem) was measured in Biceps femoris; and the water holding capacity (WHC) and meat tenderness, i.e., Shear force test, were evaluated in Longissimus dorsi. The stunning methods and gender were compared with PROC GLM (SAS Inst. Inc., Cary, NC). Meat quality was analyzed with nonparametric tests. No difference was found between gender (p>0.05). However, the stunning methods were different in the warm-carcass favoring electrical stunning. pH1h was different (p<0.05), while pH24h and meat tenderness showed no difference in relation to the stunning method (p>0.05). Electrical stunning generated meat that was less bright and with a yellow tone (L* and b* p<.0001), with a higher WHC (p=0.049). In general, results demonstrated that electrical stunning in rabbits generated less stress prior to slaughter and improved some meat characteristics. However, no influence was found in the quality of the meat. Chap.3. Objective: To characterize the cut rabbit carcass and to identify the relative importance of the cuts. Carcasses were cut 24 h postmortem; the weight of the cold-carcass (CCW), head (HE), arms (AR), legs (LE), back (BA), shoulder (SH), thorax (TH), belly flaps (BF), liver (LI) and kidneys (KI) were registered. Data were analyzed with Pearson correlations, principal component analysis, and cluster analysis. Results demonstrated that 72% of the variation in the cuts was explained by four principal components (PC). PC1 explained 37% of the total variation including CCW, HE, LE and BA; PC2 explained 16% of the variation with variables AR, TH and BF; PC3 explained 11% of the variation with KI; and CP4 explained 8% of the variation with LI and SH. The cluster analysis permitted to pinpoint two groups (CLU) of rabbits with different weight in the cuts that conform the carcass. _______________ ANALYSIS OF THE INTERACTION OF Trichoderma spp. AND Hibiscus sabdariffa. ABSTRACT: Roselle (Hibiscus sabdariffa) plants of two varieties, criolla (Vc) and tempranera (VT) were inoculated with 6 different strains of Trichoderma spp. isolated from the soil of a family farm in Tepoztlán, Morelos. The plants were kept in a greenhouse until flowering, the calyxes were collected to analyze the antioxidant compounds of polyphenolic type produced during the interaction with Trichoderma spp., the accumulation of anthocyanins, total phenols and antioxidant activity were evaluated. The results indicated that the plants of the criolla variety inoculated with the Trichoderma strain M6PMrp2 produced 8.12 g eq of ac. gallic/ 100g of dry weight (DW), while those of the tempranera variety had a lower effect on the production of phenols. Plants of the tempranera variety inoculated with the Trichoderma M1rp2 strain produced 2.82g eq of ac. gallic / 100g of dry weight. The evaluation of anthocyanins in the criolla variety plants and inoculated with Trichoderma (6 strains) values of 2.16g eq. of cyanidin 3-glucocide/ 100g of dry weight while the tempranera variety inoculated with Trichoderma produced 0.98g eq. of cyanidin 3-glucocid/ 100g of dry weight. In interaction with Trichoderma, the criolla variety showed a higher percentage in antioxidant activity compared with the tempranera variety. | es_MX |
