Replacement of fish oil in plant‐based diets for Pacific white shrimp,Litopenaeus vannamei,by stearine fish oil and palm oil

Stearine fish oil (SFO) and palm oil (PO) have emerged as promising alternatives for the replacement of fish oil (FO) in aquafeeds. This study evaluated the replacement of FO with alternative oils in practical diets for Litopenaeus vannamei. In a clear brackish water study (14.1 g/L) utilizing shrimp (0.29 ± 0.02 g, initial weight), FO was replaced by SFO at inclusion ratios of 100:0, 75:25, 50:50, 25:75, and 0:100 (FO:SFO) and PO as 90% of FO. After 55 days, no significant differences (p < 0.05) in final weight, growth, or survival of shrimp were observed. A second trial (8 weeks) in low‐salinity water (2.1 g/L) with shrimp (0.92 ± 0.02 g, initial weight) evaluated diets with 100% FO, 100% SFO, 90% PO, 90% soybean oil (SO), or 90% flaxseed oil (FXO) as a replacement for FO and four commercially produced diets with 2% of FO, SO, PO, or FXO. One treatment received half rations of the commercial FO diet, and one treatment was based entirely on natural productivity. Results show that the fatty acid profiles of the tail muscle conformed to the lipids of the feed, and highly unsaturated fatty acids (HUFAs) were preserved. Following 8 weeks of culture, there were no significant differences in production performance.     

Nano-calcium carbonate reinforced polypropylene and propylene-ethylene copolymer nanocomposites: Tensile vs. impact behavior

Improvement of both the tensile and impact strength of the same polymeric material has always been a great challenge for the plastic industry. The study focuses on the effect of incorporation of calcium carbonate nanoparticles (0.3 wt% to 15 wt%) into three polypropylene (PP) based matrices viz. PP homopolymer, propylene-ethylene (PP-PE) copolymer and the blend of PP:PP-PE (30:70) to improve their impact behavior without hampering the tensile strength much. A loss in both the tensile and impact properties was observed in PP based nanocomposite. However, PP-PE based nanocomposites showed a significant improvement in impact strength (47 %) at 10 wt% loading with a loss of tensile strength by 22 %. To minimize this loss a blend of PP:PP-PE (30:70) was explored as a matrix. At 10 wt% loading, this matrix showed an improvement of 30 % in impact strength whereas the tensile loss was minimized to 10 %. Further, silane coupling agent which promoted good interfacial adhesion was used for best compositions. The variation of crystalline morphology of the nanocomposites with various formulations was analyzed using differential scanning calorimetry and X-ray diffraction.     

Plasma and extracellular volume in calves: comparison between isotopic and 'cold' techniques.

While isotopic techniques have largely superseded traditional markers for the determination of the volume of fluid compartments in vivo, they are not always convenient, especially with diarrhoeic animals. A direct comparison was therefore made in week-old calves between Evans blue and radio-iodinated serum albumin as measures of plasma volume and thiocyanate or 24sodium as measures of extracellular fluid space. The correlation coefficients were excellent (1.00, 0.96; P < 0.001) and the calves had plasma and extracellular fluid volumes of 72 +/- 2 and 438 +/- 2 ml kg-1, respectively. The latter value is, though high, typical of young animals and comparable with other data in calves.     

Genomic variations and antigenic relationships among cytopathic rotavirus strains isolated in Quebec dairy herds.

Twelve isolates of bovine rotavirus, originating from eight dairy herds in Quebec known to have frequent epizootics of diarrhea in young calves in the last five years, were successfully propagated in cell cultures. The 12 isolates produced clear-cut plaques in BSC-1 cells and, except for one isolate, agglutinated human group "O" erythrocytes to an higher titer than bovine erythrocytes. Antisera to each isolate were produced in rabbits and used to study their antigenic relationships. All the isolates shared the group-specific immunofluorescent antigen and were antigenically related as demonstrated by the seroneutralization and hemagglutination-inhibition tests. However, the relationships to the Nebraska rotavirus was quite weak in cases of two Quebec isolates. When the genomes of the various isolates were compared by polyacrylamide gel electrophoresis, at least three different reproducible fractionation patterns could be identified.     

Effects of air temperature, air movement and artificial rain on the heat production of brushtail possums (Trichosurus vulpecula): an exploratory study

Two groups of six mature brushtail possums (Trichosurus vulpeculu) were housed in two respiration chambers, and their heat production, whole body conductance and lower critical temperatures were measured under a variety of simulated weather patterns. The possums were subjected to ambient temperatures of 30, 20 and 3 degrees C. At 20 and 3 degrees C, the animals were exposed to near still air and light winds (wind speed 0.8 and 6.7 km/h), both with, and without, simulated rain every 8 hours. The lower critical temperature in near still air lies between 7 and 10 degrees C. This temperature increases by about 2, 6 and 8 degrees C respectively for a wind velocity of 6.7 km/h, simulated rain and a combination of the two factors. Weather in New Zealand, especially in the cooler part of the year, will often produce conditions below the lower critical temperature of the thermoneutral zone of possums. This will necessitate significant increases in metabolic rate and hence food consumption or mobilisation of body fat reserves, which if not sustainable will result in the death of possums. Field studies have shown that this is often the case in the wild. It is proposed that this stress may be sufficient to decrease the resistance (especially cell-mediated immunity) of some possums and allow acceleration of the disease process in those infected with Mycobacterium bovis.     

A diet formulated from by‐products and indigenous foodstuffs for laying hens

1. The performance of six commercial stocks of laying hens fed on a diet composed of home‐produced foodstuffs, not usually used for human consumption, was compared with that of birds fed on a conventional diet.

2. The experimental diet was calculated to be low in energy and methionine and high in fibre by conventional standards. Birds ate up to 12% more of this diet, but the calculated intakes of energy and methionine were less than those of the corresponding controls.

3. White stocks fed on the experimental diet produced seven eggs less per bird than controls while the production of brown stocks was essentially unaffected.

4. The gross efficiency of energy utilisation for egg production was better with the experimental diet.     

Induction of chicken interferon by avian infectious bronchitis virus.

The ability of nine strains of avian infectious bronchitis virus (IBV) to induce chicken interferon has been investigated using Semliki Forest virus for the tests. The Beaudette, H120 and Connecticut 46 strains induced interferon in the allantoic fluids of embryonated hens' eggs, the highest titre (1 : 30) being associated with Beaudette; but these as well as the Massachusetts M-41 and H52 strains failed to yield interferon in primary monolayer cultures of chick kidney cells as did all nine strains in organ cultures of chick embryo trachea. None of six strains of IBV investigated was susceptible to the inhibitory effects of chicken interferon.     

Studies on the chiral isomers of fonofos and fonofos oxon: II. In vitro metabolism

The in vitro metabolism of the chiral isomers of fonofos and fonofos oxon in the presence of mouse liver mixed-function oxidase and serum esterase was investigated. The metabolism of ³⁵S-labeled phenyl-(S)_P-fonofos mediated by mixed-function oxidase took place stereoselectively, resulting predominantly in (R)_P-fonofos oxon. Similarly, (R)_P-fonofos was converted to (S)_P-oxon. In each case, however, a significant amount of racemization occurred. Other products were diphenyl disulfide and diphenyl disulfide oxide. In addition to stereospecificity, the oxidative metabolism of (R)_P-fonofos proceeded at a rate faster than that of (S)_P-fonofos. Stereoselective rate differences also were observed in mouse or rat serum-catalzyed degradation of the fonofos oxon enantiomers, the (S)_P isomer being degraded about twofold faster than its enantiomer. The differences in toxicities of the isomers of fonofos and fonofos oxon were consistent with the in vitro metabolism data.     

Phylogeny of the frosty pod rot pathogen of cocoa

Morphological, cytological and molecular evidence is presented which confirms that the frosty pod rot pathogen of cocoa, formerly classified as the mitosporic fungus Moniliophthora roreri (Deuteromycota), belongs to the hymenomycetous genus Crinipellis (Basidiomycota) and that two varieties should now be recognized: Crinipellis roreri var. roreri and the new variety C. roreri var. gileri . The latter was collected on Theobroma gileri , an endemic tree of submontane forests in north-west Ecuador, and can be distinguished from Ecuadorian and Peruvian isolates from cocoa ( T. cacao ) on the basis of spore morphology, incompatibility and nucleotide sequence data. As with var. roreri , meiosis is shown to occur within the dispersive and infective spore stage of var. gileri and these meiospores are interpreted to represent a much modified probasidium. In addition, in a field inoculation experiment, an isolate from T. gileri proved to be noninfective to cocoa pods when compared with positive control strains isolated from T. cacao in western Ecuador and T. bicolor in eastern Ecuador. It is concluded that var. gileri is the vestigial progenitor of the frosty pod rot pathogen of cocoa, with a host range and distribution restricted to T. gileri in the mesic forests of north-west South America.