First report of rhizopus soft rot on soursop (Annona muricata) caused by Rhizopus oryzae in México

Journal of Plant Diseases and Protection - The soursop (Annona muricata) is an important tropical plant in the Pacific and Gulf region of México. In a farmer plantation during May, severe soft...     

Effect of type of grinding of barley and dehydrated alfalfa on performance, digestion, and crude mucin ileal concentration in growing rabbits

The effects of type of grinding of barley and dehydrated alfalfa (DA) were tested in rabbits weaned at 35 d of age with an average BW of 846 ± 93 g. Four nonmedicated diets were arranged in a 2 × 2 factorial structure, with type of grinding (coarse grinding with a 4.5-mm screen or fine grinding with a 1.5-mm screen) of barley (TGB) and DA (TGDA) as the main factors. A total of 1,056 mixed-sex rabbits (264 per diet) were fattened until d 63. Most of these rabbits (216 per diet) were housed in pairs and were used only to record mortality rate. Mortality was also recorded for the remaining 192 rabbits, which were housed individually and used to determine growth performance. From this group, 100 rabbits were used to determine digestive traits. Apart from those rabbits, a different group of 88 rabbits (44 housed individually and the remaining 44 housed in pairs) was used in the digestibility trial. All rabbits in this group were used to determine ileal digestibility (13 pools of ileal digesta per diet) and ileal mucin concentration (6 pools of ileal digesta per diet), whereas only the 44 individually housed rabbits were used to assess the fecal digestibility coefficients (11 rabbits per diet). Last, a jejunal sample was excised from 32 of the 44 individually housed rabbits to determine mucosal histology. Treatments did not affect ADG, ADFI, or G:F in the entire fattening period, but in the 49- to 63-d period, the diet containing both finely ground barley and DA reduced ADFI (P=0.08) compared with the other treatments (130 vs. 137 g). Moreover, this diet increased total digestive tract (4.76%, P=0.08) and cecal content (11.3%, P=0.08) weights compared with the other 3 treatments. Pylorus (P=0.09) and mixed digesta (P=0.06) pH, respectively, were reduced from 1.53 and 1.59 to 1.37 and 1.44 when both barley and DA were finely instead of coarsely ground. Grinding both barley and DA coarsely reduced the ileal digestibility of starch (0.899 vs. 0.936, P=0.06), increased (P < 0.01) its ileal flow and content in the feces to 1.66 g/d and 7.42 g/kg of DM, respectively, and led to decreased fecal digestibility (0.932 vs. 0.951, P < 0.01) compared with fine grinding. Coarse DA shortened villi (612 vs. 704 μm, P=0.02), increased crypt depth (121 vs. 92.1 μm, P=0.01), and reduced the villus:crypt ratio (5.08 vs. 7.66, P < 0.01) compared with finely ground DA. Furthermore, the greatest ileal crude mucin (148 vs. 107 g/kg of DMI, P=0.02) and sialic acid (71.7 vs. 61.7 mg/kg of DMI, P=0.04) concentrations were reported in rabbits receiving the diet with both coarsely ground barley and DA. Finally, mortality rate was not influenced by treatments, with an average of 9.64%. In conclusion, the diet containing finely ground barley and coarsely ground DA did not increase the weight of cecal contents, resulting in increased feed intake and leading to increased ileal digestibility and reduced ileal flow of starch.     

Regrouping of pigs by body weight at weaning does not affect growth performance,carcass quality or uniformity at slaughter of heavy weight pigs

We studied the influence of pen uniformity at weaning (7.5 ± 0.6 kg vs. 7.5 ± 1.2 kg body weight (BW ± SD)) and sex on growth performance during the nursery (7.5 to 27.3 kg BW) and the fattening (27.1 to 130.5 kg BW) phases and carcass quality of barrows and castrated females (CF). During the nursery phase, pigs from the more uniform pens had lower feed efficiency (P = 0.05) than pigs from the less uniform pens. Also, barrows had higher average daily feed intake (ADFI) (P < 0.05) and average daily gain (P < 0.001) and better feed efficiency (P < 0.001) than CF. During the fattening phase, initial pen uniformity did not affect growth performance of the pigs but barrows tended (P = 0.08) to have higher ADFI and worse feed efficiency than CF. Trimmed primal cut yield tended to be higher for the more uniform pigs and better for barrows than for CF (P = 0.09). It is concluded that regrouping of the pigs at weaning according to uniformity of BW did not affect growth performance or carcass quality of the pigs at slaughter. Castrated females might be used as an alternative to barrows for the production of carcasses destined to the dry‐cured industry.     

Effect of fiber source on cecal fermentation and nitrogen recycled through cecotrophy in rabbits

The influence of fiber source on fiber digestion in rabbits was investigated. Six fibrous feedstuffs with wide differences in chemical composition and particle size were selected: paprika meal, olive leaves, alfalfa hay, soybean hulls, sodium hydroxide-treated barley straw, and sunflower hulls. Six diets were formulated to contain one of these ingredients as the sole source of fiber. To avoid nutrient imbalances, fiber sources were supplemented with different proportions of a fiber-free concentrate, based on soy protein isolate, wheat flour, lard, and a vitamin and mineral mix, to obtain diets containing at least 3% nitrogen and 5% starch. Daily soft feces excretion, and its NDF, and total and microbial nitrogen content were determined in 60 fattening rabbits (10 per diet). Seven days after the last cecotrophy control, the same animals were used to determine weight of stomach, cecum and their contents, and cecal fermentation traits (pH, VFA and ammonia concentrations, and buffer properties of cecal contents). Stepwise regression analysis showed a positive effect (P < .001) on soft feces excretion, total and microbial nitrogen concentrations in soft feces, cecal acidity, and total VFA in the cecum of dietary pectic constituents (2.9, 3.5, 2.5, .9, and 6.6%) and proportion of fine particles (< .315 mm) (1.8, .9, 1.3, .15, and .9%) per each increment of one percentage unit of the independent variables. Proportion of fine particles also increased weight of cecal contents (P < .001). Soft feces excretion and weight of stomach and of its contents increased (P < .001) by 5.2, 2.8, and 10.2% per each percentage unit increment of proportion of large particles (> 1.25 mm). Degree of lignification of NDF decreased total nitrogen concentration in soft feces and cecal VFA concentration (P < .001). Source of fiber affected cecal pH not only by its influence on the cecal concentrations of the final products of fermentation, but also through its effect on the pH of dry cecal contents (P < .001). The latter was negatively correlated with dietary proportion of fine particles, degree of lignification of NDF, and base-buffering capacity of dry cecal contents (r = -.52, -.37, and -.49, respectively). From these results, we conclude that pectic constituent concentration, degree of lignification of NDF, and particle size are the variables that best characterize the influence of the source of fiber on soft feces excretion and cecal fermentation traits in rabbits.     

Immune modulation by probiotic strains: quantification of phagocytosis of Aeromonas salmonicida by leukocytes isolated from gut of rainbow trout (Oncorhynchus mykiss) using a radiolabelling assay

A method is described for the rapid and sensitive assay of phagocytosis that utilizes radioactively labelled bacteria. With this method, we observed that phagocytosis of heat-inactivated Aeromonas salmonicida by leukocytes isolated from gut of rainbow trout fed with different viable probiotics (Lactococcus lactis subsp. lactis, Lactobacillus sakei, and Leuconostoc mesenteroides) was significantly higher (P<0.05) after 2 weeks of probiotic-feeding than the control group. However, only phagocytosis of live A. salmonicida by the leukocytes isolated from gut of rainbow trout fed with L. lactis subsp. lactis was significantly higher (P<0.05) than the control group.     

The role of probiotics in aquaculture

The increase of productivity in aquaculture has been accompanied by ecological impacts including emergence of a large variety of pathogens and bacterial resistance. These impacts are in part due to the indiscriminate use of chemotherapeutic agents as a result of management practices in production cycles. This review provides a summary of the use of probiotics for prevention of bacterial diseases in aquaculture, with a critical evaluation of results obtained to date.     

Detection and clinical evolution of scrapie in sheep by 3rd eyelid biopsy

The goal of this article was to characterize the clinical evolution of scrapie in naturally affected sheep. Eighteen sheep with scrapie diagnosed by examination of 3rd eyelid biopsy and 12 control ewes were studied throughout the duration of their disease. Diagnosis was confirmed postmortem by histopathologic, immunohistochemical, and Western blot analysis of nervous tissue. Complete clinical examinations were performed every 2 weeks for each animal, of which 3 clinical examinations per animal are reported. Those clinical signs that showed a significant frequency within the corresponding clinical examination were considered representative of each stage of the disease (ie, early, middle, and late). The representative clinical signs for the early stage were hypoesthesia in the limbs, alteration of mental status, and a body condition score <3. Remarkably, hypoesthesia in the limbs was one of the 1st signs appearing during the early clinical stage in the affected animals, even before the appearance of other signs. For the middle stage, representative signs were the same as those for the early stage, together with hyporreflexia in the limbs, cardiac arrhythmia, pruritus/wool loss, and the appearance of the nibbling reflex. Representative clinical signs for the late stage were the same as those for the early and middle stage, together with head tremors, hyperexcitability to external stimuli, ataxia or gait abnormalities, and teeth grinding. On the basis of these results, we propose the calculation of an objective clinical index that allows the differentiation among clinical stages and that could be useful for further studies. The usefulness of 3rd eyelid lymphoid tissue biopsies for sequential clinical studies in naturally scrapie-affected sheep is demonstrated.     

Effect of a reduction of dietary particle size by substituting a mixture of fibrous by-products for lucerne hay on performance and digestion of growing rabbits and lactating does

The effect of a reduction of dietary particle size by the substitution of a mixture of paprika meal, sugar-beet pulp and soya bean hulls for lucerne hay was evaluated in rabbits. Four isonutritive diets were formulated containing a decreasing proportion of large particles (> 0.315 mm) 24.1%, 22.0%, 20.6% and 18.9%. Nutrient digestibility, caecotrophy and caecal traits were determined using 9 growing rabbits per diet. Growth and lactation performance was determined in 45 weanling rabbits and 13 rabbit does per diet, respectively. The diet with the shortest particle size increased by 20% the weight of caecal contents and reduced feed intake of fattening rabbits, lactating does and suckling rabbits (21–30 d of age) by 7%, 10% and 30%, respectively, with respect to the average of the other three diets. It also decreased growth in fattening rabbits, milk production and litter weight at weaning by 6%, 13% and 18%, respectively. Feed efficiency decreased by 7% in rabbit does and was not affected during fattening, as the decrease in performance was parallel to a higher (+ 3%) digestible energy concentration in this diet. Reduction of particle size also increased NDF digestibility and caecal volatile fatty acid concentration. It is concluded that a minimal proportion of large particles (> 0.315 mm) of 20.6% is required to maximise growth and lactation performance in rabbits.