Immune responses to new vaccine candidates constructed by a live attenuated Salmonella Typhimurium delivery system expressing Escherichia coli F4, F5, F6, F41 and intimin adhesin antigens in a murine model

To construct a novel live oral vaccine candidate for the prevention of pathogenic Escherichia coli infections in neonatal piglets, an expression and secretion plasmid and an attenuated Salmonella delivery system were used. The individual E. coli genes K88ac, K99, FasA, F41 and intimin adhesins were inserted into pBP244 containing asd, lepB, secA and secB, and these plasmids were transformed into a Salmonella Typhimurium ΔcpxR Δlon Δasd. Forty female BALB/c mice were divided into four groups, A to D (ten mice per group). Groups A and B were administered with the mixture containing all constructs and the S. Typhimurium containing pBP244 only as a control, respectively. Groups C and D were primed and boosted with the mixture and the S. Typhimurium harboring pBP244 only, respectively. Each recombinant adhesin secreted from the individual candidates was confirmed by Western blot analysis. The serum IgG and secretory IgA (sIgA) titers to individual adhesins in all immunized groups were higher than those in control. Furthermore, IgG and sIgA levels in group C were higher than those in group A, and the IgG1 titers were increased in Group C but IgG2a titers were similar or decreased in Group C compared to Group A. In addition, the vaccine strains were not detected in fecal samples of any immunized mice. The novel vaccine candidates are not only highly immunogenic, but also safe for vaccinated mice and environment. In addition, the immune responses can be more efficiently induced through the booster-administration.     

Positive intraoperative cultures and canine total hip replacement: risk factors,periprosthetic infection,and surgical success

The results of closing intraoperative cultures from 27 canine total hip replacements (THR) were reviewed. The relationship between these culture results and presurgical and surgical factors, and the short- and long-term success of THR were assessed. Eleven out of 27 cases had a positive culture, but none of these 11 cases were diagnosed with periprosthetic infection at follow-up examination. The duration of the clinical signs of hip disease prior to THR was significantly greater for those cases with a positive culture (P=0.034). The incidence of positive cultures was not related to surgical success.     

Anticoccidial evaluation of halofuginone, lasalocid, maduramicin, monensin and salinomycin

The activities of five anticoccidials were compared against Eimeria species in/of chickens, in controlled in vivo and in vitro laboratory studies. Two more recent and potent market entries (maduramicin and halofuginone) were compared with three older polyether antibiotic anticoccidials (monensin, lasalocid and salinomycin). Halofuginone, lasalocid, maduramicin, monensin and salinomycin were evaluated at 3, 125, 5, 120 and 66 ppm, respectively, of active drug in the diets. At these levels, all five drugs demonstrated significant activity against Eimeria tenella, E. maxima, E. necatrix, E. brunetti and E. acervulina (in vivo). Monensin was least effective against E. tenella, and one of the lesser efficacious drugs against E. necatrix, maduramicin, was least effective against E. maxima. In studies of single Eimeria species infections, comparable weight gains were noted for the drugs. In the mixed Eimeria species infections, however, birds treated with maduramicin had significantly higher weight gains than did birds medicated with monensin. Unlike in vivo potencies, titration in vitro indicated that monensin was most potent (active at 10(-6) mcg ml-1), and maduramicin and lasalocid least potent (inactive at less than or equal to 10(-3) mcg ml-1).     

Beef quality traits of heifer in comparison with steer,bull and cow at various feeding environments

The present review has been focused largely on the sex type differences in beef quality among heifers, cows, steers and bulls in various feeding environments. Genetic groups, feeding systems and gender are the major factors that change carcass characteristics and fatty acid profiles of cattle. Studies identified that heifer beef has super characteristics in eating quality and a better healthy composition in fatty acids than steer, cow and bull. Diet influences the variation of fatty acid profile; particularly the level of polyunsaturated fatty acids (PUFA) interacts with breed and sex. Animals finished in pasture systems were reported to show better ratios of PUFA/ saturated fatty acids and n‐6/n‐3. Carcasses of roughage‐fed beef are lighter and have less marbling and lower quality grades but have higher cutability than carcasses of grain‐fed bulls. Heifers and cows are reported to deposit more fat than steers and bulls. Among males, lower production of testosterone by steers favors more fat thickness compared with bulls. Marbling greatly varies among cattle belonging to different sexes, and particularly, females have genetic makeup that efficiently controls deposition. The current review identified that heifers can be a premium beef brand, while steer beef currently take a large part of market share across the world.     

Glutamic acid supplementation recovers the reduced performance of weanling pigs fed reduced crude protein diets

This study was conducted to evaluate the supplementation of glutamic acid(Glu)to reduced protein diets on the performance of weanling pigs.One hundred and eighty crossbred weanling pigs([Yorkshire
Landrace]
Duroc,21 d old)having similar body weight(BW)of 6.45 kg were randomly allotted to 1 of 6 dietary treatments(5 pigs per pen[2 barrows and 3 gilts];6 pens per treatment)based on BW and sex during a 6-week trial.Dietary treatments consisted of positive control(PC)diet formulated to have 226.9,205.6,and 188.8 g crude protein(CP)during phases 1,2,and 3,respectively,and negative control(NC)diets with 20 g CP reduction from PC diets and addition of Glu with increasing levels,resulting in the calculated Lys-to-Glu ratios of 1:2.25,1:2.30.1:2.35,1:2.40,and 1:2.45,designated as NC,NC1,NC2,NC3,and NC4,respectively.The BW of pigs receiving PC diet was higher(P<0.05)than those receiving NC diet at d 7,21 and 42.A higher(P<0.05)average daily gain(ADG)from d 1 to 7,8 to 21,22 to 42 and during the overall experiment period was observed in pigs fed PC than NC diet.Pigs fed NC diets including the graded level of Glu linearly increased(P<0.05)BW at d 42,ADG and gain-to-feed ratio(G:F)during the overall experimental period.In addition,trends in linear increase in BW(P=0.056)at d 7 and ADG from d 1 to 7 and d 22 to 42(linear effect,P=0.081,P=0.058 respectively)were observed.A tendency in the linear increment of NH3(P=0.082)at d 21 and linear reduction in methyl mercaptans(P=0.054)emission at d 42 was observed in pigs fed NC diets supplemented with graded level of Glu.In conclusion,supplementing the reduced protein diet with Glu enhanced the growth performance in weanling pigs suggesting that supplementation of Glu can compensate the reduction of 2%CP in the basal diets.     

Identification and analysis of the Georgia 98 serotype, a new serotype of infectious bronchitis virus

Twenty-five field infectious bronchitis viruses (IBVs) similar to, but genetically distinct from, the DE072 serotype were isolated from several states in the United States from 1990 through 1999 and were examined molecularly and antigenically. A 421-bp sequence in the hypervariable region of the S1 gene was examined, and phylogenetic analysis on that region indicated that these viruses are closely related but fall into unique groups. Cross-virus neutralization testing and entire S1 sequence analysis on selected isolates further confirmed that fact, and we divided the viruses into the DE072 serotype and two other unique groups. In a vaccine protection trial, the commercially available DE072 vaccine showed less than 50% protection against viruses in one of the groups. The majority of the recent isolates belong to that group and share very low antigenic relatedness to the DE072 strain as well as other serotypes of IBV. Consequently, we designated this group as a new serotype, Georgia 98. We developed a restriction fragment length polymorphism analysis that can differentiate this new serotype from all other serotypes of IBV.     

Use of marine yeasts as an available diet for mass cultures of Moina macrocopa

A 4‐week feeding trial was conducted to test the use of marine yeasts purified from seawater and sediments as a dietary source in cultivating a cladoceran, Moina macrocopa, a potential alternative live food for fish larvae. Optimal growth conditions of two yeast strains were obtained for NaCl concentration, pH and temperature. Moina macrocopa was cultivated using different diets: marine yeasts (Debaryomyces hansenii Yeast‐14 and Candida austromarina Yeast‐16) and a commercial diet (Erythrobacter sp. Sπ‐I). The essential amino acids of both the yeast strains were nearly as great as those in M. microcopa. Further, the yeast‐fed M. macrocopa had essential amino acid profiles similar to the documented values for rotifers and Artemia enriched in microalgae and commercial diets. Erythrobacter sp. Sπ‐I lacked n‐3 polyunsaturated fatty acids, 20:5n‐3 and 22:6n‐3, which were also low but detected in both yeasts. An increase in the 20:5n‐3 [eicosapentaenoic acid (EPA)] and 22:6n‐3 [docosahexaenoic acid (DHA)] levels, compared with the levels in yeast strains themselves, was more pronounced in the 22:6n‐3 level of Moina fed the C. austromarina, resulting in a high DHA:EPA ratio. When the Moina diets were switched, their δ¹³C values shifted gradually towards the values of the switched diets. Diet switch from Erythrobacter sp. Sπ‐I to C. austromarina Yeast‐16 resulted in a more rapid turnover of Moina tissue carbon than that in the inverse case. When fed a mixed diet, the δ¹³C values of Moina tissue approached the value of marine yeasts immediately. These temporal changes in the δ¹³C values of Moina tissue indicate the preferential ingestion of marine yeasts and a selective assimilation of the carbon originated from marine yeasts. These findings suggest that marine yeasts, particularly C. austromarina Yeast‐16, are highly available to mass cultures of M. macrocopa, providing better nutritional and dietary values than the commercial diet (Erythrobacter sp. Sπ‐I).     

Influences of dietary distillers dried grain level on growth performance,body composition and biochemical parameters of juvenile olive flounder (Paralichthys olivaceus)

This study was conducted to investigate the influence of dietary distillers dried grain (DDG) level on growth and body composition of juvenile olive flounder (Paralichthys olivaceus). Five diets (designated as DDG0, DDG7, DDG14, DDG21 and DDG28) were prepared to contain 0, 70, 140, 210 and 280 g kg^?1 DDG. Three replicate groups of fish averaging 11.6 ± 0.1 g were fed one of the diets for 8 weeks. Weight gain of fish fed diets containing 70–280 g kg^?1 DDG was not different to that of fish fed DDG0 diet (P > 0.05). Feed efficiency of fish fed DDG21 and DDG28 diets was lower than that of fish fed DDG0 diet (P < 0.05). The antioxidant enzyme and digestive enzyme activities were not affected by dietary DDG levels. The results of this experiment suggested that DDG is a valuable ingredient as a candidate to replace wheat flour in the diet and could be used up to 280 g kg^?1 for the growth of olive flounder. On the other hand, if lower feed efficiency of fish fed 210–280 g kg^?1 DDG is considered, up to 140 g kg^?1 DDG in diet is recommended for optimum feed utilization of fish.