Protein digestibility of porcine colostrum by neonatal pigs

Colostrum plays an important role in neonatal growth and development. However, little is known about the digestion of macronutrients in colostrum of any species. This study was conducted with the neonatal piglet model to determine the digestibility of proteins in porcine colostrum. Twelve, 1-d-old, male piglets were selected from 3 litters (4 pigs/litter) and housed individually in metabolism crates with heating lamps to maintain a temperature of 35 °C. Colostrum (13 L) was collected from 400 sows (30 to 40 mL/sow) within 12 h postpartum after injection of oxytocin. All piglets were fed colostrum containing 0.25% (DM basis) chromium oxide as an external marker based on the following feeding program: 6 meals/d for an entire 3-d period; with 40 mL/meal for d 1 (240 mL/d), 55 mL/meal for d 2 (330 mL/d), and 70 mL/meal for d 3 (420 mL/d). Colostrum was hand-fed using baby milk bottles. Entire fecal samples with the chromium green color were collected each day after colostrum feeding. Fecal collection was terminated before the fading of the green color. Fecal samples were weighed (10.3 ± 1.0 g/pig), stored in − 20 °C, freeze-dried, and thoroughly ground for chemical analysis. Blood samples were collected at 0900 h of d 3 to obtain plasma samples for amino acid and immunoglobulin (Ig) G analysis. Digestibilities of crude protein and DM in colostrum, defined as the percentage of ingested colostral crude proteins and DM that disappeared in the gut, averaged 96.9 ± 0.4% and 98.3 ± 0.2%, respectively. Digestibility of total amino acids (protein-bound plus free amino acids) in the colostrum was 98.3 ± 0.1%, with the values being 98.5 ± 0.3, 98.2 ± 0.4, and 98.3 ± 0.3%, respectively, for Lys, Thr, and Arg. Plasma and colostral IgG content were 3.4 ± 0.3 and 3.8 ± 0.7 g/L, respectively. In conclusion, protein-bound and free amino acids in porcine colostrum were highly digestible and available to neonatal pigs.     

A suspected case of Lyme borreliosis in a hunting dog in Korea

A two-year-old male Pointer had been presented with anorexia, cachexia, and weight loss of 10-day duration. Upon physical examination, fever, lethargy, superficial lymph node enlargement, and tick infestation were noted. The only abnormality in CBC and serum chemistry analyses was mild hyperglobulinemia. Spleen was enlarged by radiography, and the lymph nodes showed neutrophilic lymphadenitis by cytological examination. A polymerase chain reaction test for babesiosis and commercial ELISA tests for Ehrlichia canis, heartworm, and Lyme disease was negative except for Lyme disease, which was verified by both an IFA-IgG test and a quantitative C₆ assay. Doxycycline was administered for 2 weeks and the recovery was uneventful. Post-treatment C₆ titer decreased to within normal limits.     

Effect of dietary nutrient composition on the growth of olive flounder (<Emphasis Type="Italic">Paralichthys olivaceus</Emphasis>) with different feeding regimes

We have examined the effect of dietary nutrient composition on the growth, body composition and blood chemistry of juvenile olive flounder (Paralichthys olivaceus) maintained on two different feeding regimes. Three experimental diets [HP (high protein), HE (high energy) and IPE (intermediate protein and energy)] were crossed in a two-factor design with the two feeding regimes, which consisted of 2WS + 2WF (2-week starvation and then 2-week feeding) and 4WS + 4WF (4-week starvation and then 4-week feeding)], for 8 weeks. The total days of feeding in all treatments were the same. The final weight of fish was affected by feeding regime, but not by dietary nutrient composition. Long-term starving and feeding (the 4WS + 4WF treatments) yielded higher growth than the alternating short-term starving and feeding regime (2WS + 2WF treatments). The feed consumption of fish was affected by dietary nutrient composition, but not by feeding regime, while the feed efficiency of fish was affected by feeding regime, but not by dietary nutrient composition. Moisture, crude protein and crude lipid contents of the liver of the fish were affected by dietary nutrient composition, but not by feeding regime.     

Haematological and biochemical alterations in Korean catfish, Silurus asotus, experimentally infected with Edwardsiella tarda

This study determined the haematological changes in Korean catfish, Silurus asotus , experimentally infected with Edwardsiella tarda . Twenty-four or 48 h after infection with 1 × 10⁴ colony-forming units (CFU) mL⁻¹ of E. tarda , the fish were anaesthetized and the blood was collected. The haematological and biochemical tests included haematocrit (Ht), haemoglobin (Hb), leucocyte counts (Lc), total calcium (Ca), total protein (TP) concentration, alkaline phosphatase (ALP), glucose (GLU), aspartate aminotransferase, lysozyme and differential leucocyte populations. After 24- and 48-h infection, the values of Ht, Hb, Lc, TP, ALP and GLU were significantly decreased with respect to the control. Aspartate aminotransferase and lysozyme activity in both the 24- and 48-h groups exhibited higher levels compared with those in the control. However, the bacterial infection did not induce any significant alteration in the Ca concentration. After the 48-h infection, neutrophils and macrophage populations were reduced whereas lymphocytes were increased with respect to those in the control and the 24-h infection groups. The present study demonstrates that E. tarda infection causes haemato-biochemical responses that are related to the general physiological condition and defence system in catfish.     

Effects of dietary administration of Macsumsuk® on growth and stress to low salinity and low dissolved oxygen in whiteleg shrimp,Litopenaeus vannamei (Boone, 1931) juveniles

An 8‐week study was conducted to explore the results of Macsumsuk^® as a feed additive on the stress tolerance and growth of Litopenaeus vannamei in 15 culture tanks of 36 L each. Three hundred shrimp averaging 0.1 ± 0.01 g were fed with five isonitrogenous (48.38 ± 0.38% CP) diets (in triplicate groups) containing kaolinite (Macsumsuk^®) at 0%, 0.3%, 0.6%, 1.2% and 2.4%, namely Mk₀, Mk_0.3, Mk_0.6, Mk_1.2 and Mk_2.4. Specific growth rate (SGR) and weight gain (WG) of shrimp fed diets Mk_1.2 and Mk_2.4 were significantly better than those of shrimp fed diet Mk₀ (p < .05). However, SGR and WG of shrimp fed diets Mk_0.6, Mk_1.2 and Mk_2.4 were not significantly different. Protein efficiency ratio (PER) and feed efficiency (FE) of shrimp fed diets Mk_1.2 and Mk_2.4 were significantly better than those of shrimp fed diets Mk₀, Mk₀.₃ and Mk_0.6. Furthermore, the survival of shrimp fed diet Mk_2.4 was significantly lower than that of shrimp fed diet Mk_0.6 (p < .05). Cumulative mortality of shrimp fed diet Mk_1.2 was significantly lower than that of shrimp fed diet Mk₀ at 1–1.5 hr post‐stress to low dissolved oxygen (from 6.1 mg/L to 2.9 mg/L) and 4–5 hr post‐stress to low salinity (from 32‰ to 1‰) (p < .05). The optimum dietary Macsumsuk^® level for juvenile L. vannamei was determined as 1.97% by the polynomial regression analysis of weight gain.     

Efficacy of a polyvalent injectable vaccine against Flavobacterium psychrophilum administered to rainbow trout (Oncorhynchus mykiss L.)

Flavobacterium psychrophilum is one of the most important pathogens affecting cultured rainbow trout (Oncorhynchus mykiss). Recent information from UK salmonid farms showed country‐wide distribution of genetically and serologically divergent clones, which has hampered the development of a vaccine for rainbow trout fry syndrome. The current study assessed the efficacy of an injectable polyvalent vaccine containing formalin‐inactivated F. psychrophilum in rainbow trout. The vaccine was formulated with an oil adjuvant (Montanide ISA 760VG) or formalin‐killed cells alone. Duplicate groups of trout (60 ± 13 g) were given phosphate‐buffered saline or vaccine formulated with Montanide by intra‐peritoneal (i.p.) injection and challenged by intra‐muscular (i.m.) injection with a homologous and a heterologous isolate of F. psychrophilum at 525 degree days post‐vaccination (dd pv). Significant protection was achieved in vaccinated fish (p = 0.0001, RPS 76% homologous, 88% heterologous). Efficacy of the adjuvanted vaccine was also demonstrated by heterologous challenge at 1155 dd pv resulting in 100% protection, whereas survival in the un‐adjuvanted group was not significantly different from control fish. Levels of specific antibody at 1155 dd pv, as measured by ELISA, were significantly higher in the fish vaccinated with adjuvant when compared with unvaccinated fish.     

The induction of Hsp70 synthesis by non‐lethal heat shock confers thermotolerance and resistance to lethal ammonia stress in the common carp,Cyprinus carpio (Linn)

Exposure to heat‐shock protein (Hsp) stimulating factors induces Hsp accumulation and confers tolerance to lethal ammonia stress on the common carp Cyprinus carpio. This study investigated whether a non‐lethal heat shock bestowed similar protective effects against ammonia and induced thermotolerance, both thought to be rendered by increased amounts of Hsps. The 30‐min lethal temperature (30 min LHT) and 1‐h lethal ammonia concentration (1 h LCT) for this species occurred at 41°C and 14.2 mg/L NH₃ respectively. Heating juvenile carp (5 cm) from 28°C to 32, 34 and 38°C, with a subsequent 8‐h recovery period augmented tolerance to lethal heat and ammonia perturbation by two to threefold as compared with animals held at 28°C. Protection occurred in conjunction with Hsp70 accumulation in gills, substantiating the role of this Hsp in enhancing the stress tolerance of common carp.     

Feeding Artemia franciscana (Kellogg) larvae with bacterial heat shock protein, protects from Vibrio campbellii infection

Among their numerous physiological effects, heat shock proteins (Hsps) are potent immunomodulators, a characteristic reflecting their potential as therapeutic agents and which led to their application in combating infection. As an example, the up-regulation of endogenous Hsp70 in the branchiopod crustacean Artemia franciscana (Kellogg) is concurrent with shielding against bacterial infection. To better understand this protective mechanism, gnotobiotic Artemia were fed with Escherichia coli treated to over-produce different prokaryotic Hsps. This was shown to increase larval resistance to experimental Vibrio campbellii exposure. Immunoprobing of Western blots showed that the enhanced resistance to V. campbellii correlated with DnaK production in E coli . A definitive role for DnaK was then demonstrated by feeding Artemia larvae with transformed bacteria over-producing only this protein, although other Hsps such as DnaJ and grpE also provided tolerance against Vibrio infection. Feeding of bacteria synthesizing selected Hsps is therefore suggested as an alternative to antibiotic use as a means of enhancing resistance of Artemia larvae to bacterial infection, which may have potential applications in aquaculture.     

Preliminary analysis of recombinant β-tubulin of Pseudocohnilembus persalinus (Ciliophora: Scuticociliatida) as a vaccine antigen candidate against scuticociliatosis

The recombinant β-tubulin of Pseudocohnilembus persalinus was investigated to test whether tubulin could be a suitable antigenic target against scuticociliatosis. The cDNA of P. persalinus β-tubulin has an open reading frame of 1332 bp and had 15 TAA triplets code for glutamine (Q). All 15 TAA/Q triplets of the β-tubulin cDNA were mutated to universal CAA/Q triplets by site-directed mutagenesis and the mutated β-tubulin was expressed in Escherichia coli as a fusion with glutathione S-transferase (GST-BTU). In Western blot analysis, rat sera immunized with recombinant GST-BTU reacted with reduced β-tubulin of P. persalinus. The immunized rat sera showed higher parasiticidal activity than those of control. Ciliates preincubated with heat-inactivated immune sera showed significantly lower proliferation than ciliates preincubated with control sera when exposed to naïve rat sera as a complement source. The present results suggest that the recombinant β-tubulin of scuticociliates may be used as a target antigen for development of vaccine against scuticociliatosis.     

Attractiveness of various protein sources to juvenile rockfish (Sebastes schlegeli,Hilgendorf 1880)

ABSTRACT

The attractiveness of various protein sources of 16 feed ingredients was determined in juvenile rockfish (Sebastes schlegeli) by using reinforced acrylic tank composed of three equally divided rectangular attracting chambers and an acclimatization chamber. Thirty fish were held in the acclimatization chamber at a time and tournament comparison of feed ingredients was applied to evaluate attractiveness. Jack mackerel (JM) (40.0%), sardine (SM) (33.3%), Pollack (PM) (40.0%), shrimp (SHM) (36.7%), mussel meal (40.0%) and oyster (43.3%) meals achieved the highest feeding attractiveness to rockfish in the 1^st through 6^th preliminary test, respectively. JM (40.0%), SHM (36.7%), squid meal (SQM) (33.3%), SM (40.3%), PM (40.0%) and PM (36.7%) achieved the highest feeding attractiveness to fish in the 7^th through 12^th preliminary test, respectively. Among the top five feed ingredients showing high attractiveness to rockfish, JM achieved higher attractiveness than PM and SHM in the 1^st trial. In the 2^nd trial, attractiveness of JM to rockfish was higher than SM and SQM. SM achieved higher attractiveness to rockfish than SQM, but not different from PM throughout the 30-min observation in the 3^rd trial. The strongest feeding attractant response of rockfish was observed in JM, followed by SM, SQM, PM, and SHM, in order among various feed ingredients.