Comparison of morphology, viability, and function between blood and milk neutrophils from peak lactating goats

The morphological features of blood and milk neutrophils from peak lactating goats were compared using light microscopy, scanning electron microscopy and flow cytometry in order to investigate the cytological changes of neutrophils after migration into the mammary gland. The kinetics of reactive oxygen intermediates (ROI) generation and gelatinase release of blood and milk neutrophils, with or without stimulation of phorbol 12-myristate, 13-acetate ester (PMA), were used to characterize their responses to inflammatory stimuli. Neutrophils isolated from goat milk were highly segmented and contained multi-lobed nuclei. Ultrastructurally, milk neutrophils were more ruffled on the surface compared to blood neutrophils. Approximately 30% of milk neutrophils were undergoing cell death, either necrosis or apoptosis, in contrast to 8% of blood neutrophils. The ROI production of activated milk neutrophils peaked earlier than blood neutrophils, but the duration and the intensity were much less. Neutrophils from both sources augmented the release of gelatinase in response to PMA (1 ng/mL). However, the amount of gelatinase released from milk neutrophils was lower (P < 0.05) than that of blood neutrophils. In summary, more neutrophils become apoptotic and necrotic in the mammary gland, presumably due to spontaneous aging, the process of diapedesis, and the interaction with milk components. Milk neutrophils have impaired functionalities in comparison with blood neutrophils. The information is relevant when studying mammary gland immunity and related diseases, such as mastitis.     

Effects of chromium nicotinate on performance, carcase characteristics and blood chemistry of growing turkeys

1. The objective of this trial was to study the effects of chromium nicotinate (Cr) supplementation on the performance, carcase characteristics and blood constituents of 9 to 22 week-old male turkeys. 2. Fifty-four 8-week-old male turkeys weighing 2.9 +/- 0.28 kg were allocated at random into 9 groups with 3 dietary treatments and 3 replicates. The dietary treatment was different dietary concentrations of chromium in the basal diet, to provide 0 (control), 1 or 3 mg/kg. The feeding trial lasted for 14 weeks. 3. Results showed that 1 mg/kg chromium supplementation significantly improved weight gain and food intake at 9 to 18 weeks of age but did not significantly influence performance at 19 to 22 week of age. The breast and thigh muscle were significantly increased in birds receiving 1 mg/kg chromium supplementation but were decreased by 3 mg/kg of supplementation. 4. Dietary chromium supplementation did not significantly influence other serum constituents, including insulin, HDL, VLDL+LDL, HDL-C, VLDL-C+LDL-C, total protein, albumin, and gamma-globulin at 18 and 22 weeks of age. 5. The serum triacylglycerol (TG) and uric acid contents were significantly increased, while glycerol and alpha-globulin were significantly reduced by 3 mg/kg chromium supplementation. However, 1 mg/kg chromium supplementation significantly reduced serum cholesterol and glycerol at 18-weeks old. At 22 weeks of age, 1 mg/kg chromium supplementation significantly increased serum glucose and decreased the uric acid concentration whereas 3 mg/kg chromium supplementation significantly increased the creatinine concentration and decreased beta-globulin concentration.     

Oral immunization using formalin-inactivated Actinobacillus pleuropneumoniae antigens entrapped in microspheres with aqueous dispersion polymers prepared using a co-spray drying process

Oral-vaccine microspheres based on formalin-inactivated Actinobacillus pleuropneumoniae serotype 1 (AP-1) antigens and enteric-coated polymers were prepared using a co-spray drying process. We evaluated using this for a peroral vaccine. We measured specific-antibody titers and protection from challenge in mouse and pig models. In mice (24 per group), a subcutaneous aluminum-adjuvant vaccine or oral vaccination with three doses of AQ6-AP microspheres provided similar protection against intranasal challenge with 5 x 10(8) colony-formation units (cfu) of AP-1 bacterial culture broth. Two weeks after four oral vaccinations with 600 mg of AQ6-AP microsphere acetate solution (containing formalin-inactivated AP-1 antigens of 1.0 x 10(10) cfu bacterial broth), pigs (9 per group) were challenged intranasally with 1 ml of AP-1 bacterial culture broth (5 x 10(9) cfu). The clinical signs, percentage of pig survival ratio, lung lesion areas, and microscopic examinations indicated that the oral AQ6-AP vaccine provided more protection than vaccinating pigs intramuscularly with AP-1 aluminum vaccine.     

Effects of sources of protein and enzyme supplementation on protein digestibility and chyme characteristics in broilers

1. The purpose of this study was to evaluate the effects of protein source and enzyme supplementation on protein digestibility and chyme characteristics in broilers. 2. One hundred and twenty growing (13 d old) and 60 finishing (34 d old) Arbor Acre strain commercial male broilers were selected and placed into individual metabolic cages. 3. The experiment was a 5 x 2 factorial arrangement with 5 different sources of protein: casein, fish meal, soybean meal (SBM), soy protein concentrate (SPC), maize gluten meal (MGM) and two levels of protease (bromelain), 0 and 65 CDU/kg diets. 4. The diets were iso-nitrogenous and semi-purified, with Cr2O3 as an indicator for determination of ileal digestibility and chyme characteristics. 5. Apparent ileal protein digestibility (AIPD) in both growing and finishing chickens was highest on the casein diet, followed by fish meal, SBM, SPC and MGM. 6. Enzyme inclusion did not improve protein digestibility, but significantly decreased the digesta pH value in the gizzard and increased pH in the ileum in the 3-week-old broilers. 7. The digesta pH values in the gizzard and duodenum were significantly lower in the SBM and fish meal groups compared with the other protein groups. The molecular weight distribution pattern of the soluble protein in the chyme of the gastrointestinal (GI) segments showed a similar trend, regardless of the enzyme inclusion or the stage of growth. 8. The molecular weight profile of soluble protein changed dynamically in the casein fed broilers from the gizzard to ileum and the low molecular weight proteins, < 7 kDa, reached maximum levels at the ileum. The molecular weight profile of the soluble protein in the SBM and SPC changed between the jejunum and the ileum and in the intermediate molecular soluble protein weight (7 to 10 kDa) was significantly decreased. This indicated that the hydrolysis process began from the middle to the posterior end of the small intestine. 9. Similar profiles were also shown with fish meal protein. The pattern of distribution, however, did not show any prominent change in the GI segments of the MGM group. 10. The pepsin, trypsin and chymotrypsin protease activity in the gizzard and duodenum were highest in the casein group and lowest in the MGM group as compared with the other protein groups. 11. The rate change in the patterns of molecular weight distribution in soluble protein and the digestive enzyme activity provide indications of the partial digestibility of different protein sources. The exogenous enzyme, bromelain, did not show any beneficial effect on protein digestion.     

Effects of porcine reproductive and respiratory syndrome virus (isolate tw91) on porcine alveolar macrophages in vitro

To verify the role of porcine reproductive and respiratory syndrome virus (PRRSV) infection on pulmonary defense mechanisms, alterations in the viability, morphology, and various functions of porcine alveolar macrophages (AMs) were evaluated in vitro for 2-72 h after exposure to a Taiwan isolate, tw91, at a multiplicity of infection (MOI) of 0.1. A low but constant rate of infection, around 5%, was seen in AMs from the PRRSV-infected group throughout the study. When compared with a mock-infected group, AMs from the PRRSV-infected group had a significantly lower viability at 18-72 h post-infection (HPI) as determined by trypan blue dye exclusion. Also during this time period, the cells showed morphological changes, including rounding, bleb formation, and rupture. The phagocytic and microbicidal capacity of AMs against Candida albicans was significantly inhibited after 6 HPI. Although the total amount of superoxide anion (O2-) and hydrogen peroxide (H2O2) produced by the AMs was reduced after 18 and 12 HPI, respectively, the amount of production was enhanced in both reactive oxygen species on a per viable cell basis after 12 HPI. In contrast, the level of bioactive tumor necrosis factor alpha (TNF-alpha) secretion, either total or on a per viable cell basis, was markedly reduced soon after PRRSV infection, up to 36 HPI, followed by a rebound thereafter. Prostaglandin E2 (PGE2) production was enhanced, both in total and on a per viable cell basis, in the first 6 h of infection, especially at 2 HPI. However, it became lower than that of the control after 36 HPI. The results indicated that PRRSV infection could cause, directly and/or indirectly, not only death of AMs but also adverse alterations in their morphology and function, although some of the effects seemed to be reversible. Because AMs are crucial to the host against airborne pathogens, PRRSV infection may potentially predispose pigs to secondary pulmonary infections.     

Spatio-temporal distribution of sergestid shrimp Acetes intermedius in the coastal waters of southwestern Taiwan

SUMMARY: Spatio-temporal variation of the sergestid shrimp Acetes intermedius in the coastal waters of southwestern Taiwan was investigated based on 1546 samples collected by 13 commercial fishing vessels from July to October 1996. Adult sergestid shrimp started a down-estuary migration with the increased river discharge associated with heavy summer rainfall. Fishing season for this species was to commence after that. In July, the shrimp stock was found on the shallow continental shelf off Tungkang and Fangshan. They mainly aggregated in Kaoping Canyon off Tungkang during August and September occurring at very high densities. In October, the shrimp returned to the coastal waters off Tungkang and Fangshan at lower densities. The heavy rainfall is a factor that triggers the shrimps to make a down-estuary migration that could reduce competition for food between adults and their offspring during the period of high river discharge. When the northeast monsoon prevailed, the sergestid shrimp moved back to the estuaries and the fishing season was terminated.     

Structure and function of antimicrobial peptide penaeidin-5 from the black tiger shrimp Penaeus monodon

The gene for penaeidin-5, an antimicrobial peptide comprising 55 amino acids, was isolated from the hemocyte of black tiger shrimp (Penaeus monodon). RT-PCR expression tests revealed that penaeidin-5 was produced in hemocytes, gills, the intestine and muscle. Western blot analysis confirmed the panaeidin-5 was aboundantin hemocytes, the intestine and hemolymph. Immunohistochemistry revealedpenaeidin-5 in the cuticle and gills that are considered primary defense barriers. The deduced amino acid sequence of penaeidin-5 included a proline-rich N-terminal domain and a carboxyl-domain that contained six cysteine residues. Circular dichrosim analysis revealed an -helix in its secondary structure and the predicted 3D structure indicated two-disulfide bridges in the -helix. Based on the sequence of penaeidin-5 peptide cDNA, synthetic penaeidin-5 was prepared to carry out functional tests. The synthetic peptide had efficient bacteriostatic and bactericidal activity against Aerococcus viridans, and also inhibited the growth of two filamentous fungi, Fusarium pisi and Fusarium oxysporum. To measure penaeidin-5 in vivo, black tiger shrimp were challenged with Vibrio alginolyticus and A. viridans. At 3 h post-challenge, penaeidin-5 was induced and bacterial numbers decreased significantly by 12 h and 24 h.     

Coldness index does not indicate the upper limit of evergreen broad-leaved forest on a subtropical island

Many ecologists in East Asia consider that Kira’s coldness index (CI) of ?10 °C month agrees well with the northward and upward limits of evergreen broad-leaved forest (EBLF). It is of interest to establish whether CI is an effective indicator of the upper limit of EBLF in a tropical-to-temperate transitional island. A case study in Taiwan was conducted through a comparison of CI layers with field vegetation information. The results from spatial analysis revealed that the location of CI = ?10 isotherm was approximately 3,381 m a.s.l., within the Abies zone. The analysis of plots showed that vegetation near CI = ?10 isotherm was evergreen coniferous pure forest with 99.9 % relative dominance. The CI = 0 isotherm lay at approximately 2,594 m a.s.l., close to the boundary between the Tsuga–Picea and upper Quercus zones, with the CI = 0 isotherm in the transformation zone between evergreen coniferous and broad-leaved trees. However, the vegetation near CI = 0 isotherm tended more toward coniferous forest showing a total relative dominance of 78.26 %. The two-way cluster dendrogram of vegetation plots revealed identical results. The preceding evidence, combined with the spatial pattern of 3,564 plots along CI and elevation gradients, made it clear that CI did not indicate the upper limit of EBLF in Taiwan. Other information on the CI criterion are discussed. To explore the differentiation of altitudinal vegetation, further research should be made to connect ecoclimatic factors such as effective warmth index with information from vegetation plots.