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1.
The present study investigated the replacement of soybean meal with combinations of two or three alternative protein sources in diets for pond‐raised hybrid catfish, ♀ Ictalurus punctatus × ♂ Ictalurus furcatus. Alternative protein sources evaluated included cottonseed meal, distillers dried grains with solubles (DDGS), peanut meal, and porcine meat and bone meal (PMBM). Hybrid catfish fingerlings with a mean initial weight of 35 g/fish were stocked into 25 earthen ponds (0.04 ha) at a density of 14,826 fish/ha. Fish were fed once daily to apparent satiation for 166 d. No significant differences were observed for total diet fed, net yield, weight gain, survival, carcass yield, fillet yield, or fillet proximate composition among dietary treatments. Results show soybean meal may be completely replaced by combinations of cottonseed meal and one or two other alternative protein sources including DDGS, peanut meal, and PMBM in the diet without markedly affecting production and processing characteristics and fillet proximate composition of pond‐raised hybrid catfish. These alternative diets may be used during foodfish production when prices are favorable.  相似文献   
2.
This study examined the effects of feeding frequency (daily versus every other day [EOD]) on nutrient digestibility/availability of channel catfish, Ictalurus punctatus, reared at optimal (30 C) and suboptimal (24 C) temperatures. A 28% protein practical diet was used as the test diet, and chromic oxide was used at 0.75% of the diet as a maker. Twenty channel catfish of a mean weight of 141 g/fish were stocked into 12 flow‐through aquaria (110 L). Fish were fed daily or EOD to apparent satiation for 7 d before fecal samples were collected by the dissection method. Fish fed EOD to apparent satiation consumed more diet on days fed than those fed daily, and fish reared at 30 C consumed more diet than those reared at 24 C. Neither feeding frequency nor water temperature significantly affected apparent digestibility coefficients for energy and protein and apparent availability coefficients for total amino acids. Results show no advantage by feeding EOD over feeding daily on nutrient digestibility and diet utilization efficiency.  相似文献   
3.
Observations on transplacental infection with bluetongue virus in sheep   总被引:1,自引:0,他引:1  
Twenty-four ewes were inoculated with 1 of 2 strains of bluetongue virus type 4 at 40, 60, or 80 days of gestation. Two ewes aborted, 2 ewes died, and 1 was killed during the experiment, but their fetuses were recovered. At term, 2 mummified fetuses, 4 dead lambs, and 17 clinically healthy lambs were produced by 12 sheep, and the remaining 7 sheep were barren. Porencephaly and cerebellar dysgenesis were found in term lambs born to sheep inoculated at 40 and 60 days of gestation. Radiographic examination of 12 fetuses showed developmental ages far less than their chronologic age; 8 fetuses had skeletal growth-retardation lines, which were also observed in the dead lambs. A systemic lymphoreticular hyperplasia was observed in the dead lambs and in all lambs at 12 weeks of age; in 4 of the latter, granulomatous reactions were present in the liver and kidney. Lungs of the full-term lambs were reduced in weight and showed poor alveolar development and mononuclear cell infiltration, which persisted in the 12-week-old lambs. It was concluded that bluetongue virus is capable of causing not only gross abnormalities of the CNS, but also generalized growth retardation and fetal lymphoreticular hyperplasia.  相似文献   
4.
A field study utilizing 145 mares of various age and breeding status was conducted to determine reproductive performance under native range conditions with only limited supplemental feeding. All mares had an average initial body condition score of 4.5 and a final score of 5.1 by the time breeding was completed and mares returned to pasture. Average foaling rate was 80%, and mares that had not conceived during the previous breeding season had a foaling rate of 94%, which was higher (P<.05) than 74% for lactating mares. Mares 16 years and older had a significantly lower foaling rate (P<.05) than younger mares. Old mares that were lactating at time of breeding had only a 37% foaling rate, which was less (P<.05) than for young lactating mares. The 94 mares bred by natural cover or artificial insemination that actually foaled required 1.43 cycles per conception. Lactating mares in the oldest age group required more cycles per conception (P<.05) than open mares, and these older, lactating mares also required more cycles per conception than younger mares with foals at side. Those mares diagnosed as pregnant or open at 45 days post breeding had a pregnancy rate of 97%. Average pregnancy loss for all mares was 7.7%. These data indicate that lactating mares in moderate body condition tended to skip a breeding season and that a body condition score of 5 was only marginally acceptable, especially in the case of lactating mares. Authors' address: Equine Science Program, Department of Animal Science, Texas Agricultural Extension Service, Texas A&M University, College Station, TX 77843. Technical Article Number 30023, Texas Agr. Exp. Sta.  相似文献   
5.
Fifty dogs showing clinical signs of spinal disease were investigated by myelography, using iopamidol. In 27 cases the technique was considered worthwhile. Of the 19 dogs not subjected to surgery or euthanasia as a result of the findings, three suffered seizures during recovery from anaesthesia, eight deteriorated in neurological condition and one suffered permanent respiratory arrest as a result of extensive subarachnoid haemorrhage.  相似文献   
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A study was conducted to evaluate low‐protein traditional or alternative diets for pond‐raised hybrid catfish, Ictalurus punctatus × Ictalurus furcatus. Three 24% protein diets containing decreasing levels of soybean meal (30, 20, and 15%) and increasing levels of cottonseed meal and corn germ meal were compared with a 28% protein control diet. Hybrid catfish fingerlings (mean initial weight = 71 g/fish) were stocked into 20 earthen ponds (0.04 ha) at a density of 14,826 fish/ha with five ponds per dietary treatment. Fish were fed once daily to apparent satiation for a 191‐d growing season. There were no significant differences in total diet fed, net yield, weight gain, feed conversion ratio (FCR), survival, or fillet proximate nutrient composition among dietary treatments (P ≥ 0.10). However, regression analysis showed for fish fed 24% protein diets there was a linear increase in FCR as soybean meal levels decreased (P = 0.06). Compared with fish fed the 28% protein control diet, fish fed 24% protein diets had lower carcass and fillet yield. Results demonstrate a 24% protein alternative diet containing 20% soybean meal may be substituted for 28% protein diets for hybrid catfish during food fish production.  相似文献   
9.
REASON FOR PERFORMING STUDY: West Nile virus (WNV) infection is endemic and able to cause disease in naive hosts. It is necessary therefore to evaluate the safety of new vaccines. OBJECTIVES: To establish: 1) the safety of a modified live Flavivirus/West Nile virus (WN-FV) chimera by administration of an overdose and testing for shed of vaccine virus and spread to uninoculated sentinel horses; 2) that this vaccine did not become pathogenic once passaged in horses; and 3) vaccine safety under field conditions. METHODS: There were 3 protocols: 1) In the overdose/shed and spread study, horses were vaccinated with a 100x immunogenicity overdose of WN-FV chimera vaccine and housed with sentinel horses. 2) A reversion to virulence study, where horses were vaccinated with a 20x immunogenicity overdose of WN-FV chimera vaccine. Horses in both studies were evaluated for abnormal health conditions and samples obtained to detect virus, seroconversion and dissemination into tissues. 3) In a field safety test 919 healthy horses of various ages, breeds and sex were used. RESULTS: Vaccination did not result in site or systemic reactions in either experimental or field-injected horses. There was no shed of vaccine virus, no detection of vaccine virus into tissue and no reversion to virulence with passage. CONCLUSIONS: WN-FV chimera vaccine is safe to use in horses with no evidence of ill effects from very high doses of vaccine. There was no evidence of reversion to virulence. In addition, administration of this vaccine to several hundred horses that may have been previously exposed to WNV or WNV vaccine resulted in no untoward reactions. POTENTIAL RELEVANCE: These studies establish that this live attenuated Flavivirus chimera is safe to use for immunoprophylaxis against WNV disease in horses.  相似文献   
10.
REASON FOR PERFORMING STUDY: West Nile virus (WNF) is a Flavivirus responsible for a life-threatening neurological disease in man and horses. Development of improved vaccines against Flavivirus infections is therefore important. OBJECTIVES: To establish that a single immunogenicity dose of live Flavivirus chimera (WN-FV) vaccine protects horses from the disease and it induces a protective immune response, and to determine the duration of the protective immunity. METHODS: Clinical signs were compared between vaccinated (VACC) and control (CTRL) horses after an intrathecal WNV challenge given at 10 or 28 days, or 12 months post vaccination. RESULTS: Challenge of horses in the immunogenicity study at Day 28 post vaccination resulted in severe clinical signs of WNV infection in 10/10 control (CTRL) compared to 1/20 vaccinated (VACC) horses (P<0.01). None of the VACC horses developed viraemia and minimal histopathology was noted. Duration of immunity (DPI) was established at 12 months post vaccination. Eight of 10 CTRL exhibited severe clinical signs of infection compared to 1 of 9 VACC horses (P<0.05). There was a significant reduction in the occurrence of viraemia and histopathology lesion in VACC horses relative to CTRL horses. Horses challenged at Day 10 post vaccination experienced moderate or severe clinical signs of WNV infection in 3/3 CTRL compared to 5/6 VACC horses (P<0.05). CONCLUSIONS: This novel WN-FV chimera vaccine generates a protective immune response to WNV infection in horses that is demonstrated 10 days after a single vaccination and lasts for up to one year. POTENTIAL RELEVANCE: This is the first USDA licensed equine WNV vaccine to utilise a severe challenge model that produces the same WNV disease observed under field conditions to obtain a label claim for prevention of viraemia and aid in the prevention of WNV disease and encephalitis with a duration of immunity of 12 months.  相似文献   
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