Consumer perception versus scientific evidence of farmed and wild fish: exploratory insights from Belgium

The increasing number of marketable fish being supplied from aquaculture is a response to the increasing demand for healthy food and is filling the gap left by depleting natural fish stocks. Little is known about the awareness and perception of the consumer in terms of farmed fish versus fish from capture fisheries. The consumer's subjective point of view is of overriding importance for the production system and product acceptance as well as for future market success. In this paper consumer perception in Belgium is explored and compared against scientific evidence of farmed versus wild fish. Primary data were collected through a consumer survey (April 2003) and focus group discussions (May 2004) with Belgian consumers. The majority of the consumer sample reported no perceived differences between farmed versus wild fish. However, mean perception scores were slightly in favour of wild fish on the attributes taste, health and nutritious value, in particular among consumers aged 55 years and older. The availability of farmed fish was perceived to be better than that of wild fish, while the consumer's perception of safety did not differ between farmed and wild fish. The focus group discussions indicated that consumers’ opinions and beliefs about farmed fish are mainly based on emotion and image transfer from intensive terrestrial livestock production rather than on awareness and factual knowledge of aquaculture.

Fucose-Rich Sulfated Polysaccharides from Two Vietnamese Sea Cucumbers Bohadschia argus and Holothuria (Theelothuria) spinifera: Structures and Anticoagulant Activity

Fucosylated chondroitin sulfates (FCSs) FCS-BA and FCS-HS, as well as fucan sulfates (FSs) FS-BA-AT and FS-HS-AT were isolated from the sea cucumbers Bohadschia argus and Holothuria (Theelothuria) spinifera, respectively. Purification of the polysaccharides was carried out by anion-exchange chromatography on DEAE-Sephacel column. Structural characterization of polysaccharides was performed in terms of monosaccharide and sulfate content, as well as using a series of non-destructive NMR spectroscopic methods. Both FCSs were shown to contain a chondroitin core [→3)-β-d-GalNAc-(1→4)-β-d-GlcA-(1→]_n bearing sulfated fucosyl branches at O-3 of every GlcA residue in the chain. These fucosyl residues were different in pattern of sulfation: FCS-BA contained Fuc2S4S, Fuc3S4S and Fuc4S at a ratio of 1:8:2, while FCS-HS contained these residues at a ratio of 2:2:1. Polysaccharides differed also in content of GalNAc4S6S and GalNAc4S units, the ratios being 14:1 for FCS-BA and 4:1 for FCS-HS. Both FCSs demonstrated significant anticoagulant activity in clotting time assay and potentiated inhibition of thrombin, but not of factor Xa. FS-BA-AT was shown to be a regular linear polymer of 4-linked α-L-fucopyranose 3-sulfate, the structure being confirmed by NMR spectra of desulfated polysaccharide. In spite of considerable sulfate content, FS-BA-AT was practically devoid of anticoagulant activity. FS-HS-AT cannot be purified completely from contamination of some FCS. Its structure was tentatively represented as a mixture of chains identical with FS-BA-AT and other chains built up of randomly sulfated alternating 4- and 3-linked α-L-fucopyranose residues.     

Field detection of resistance to isometamidium chloride and diminazene aceturate in Trypanosoma vivax from the region of the Boucle du Mouhoun in Burkina Faso

A longitudinal study assessed the chemoresistance to isometamidium chloride (ISM) and diminazene aceturate (DA) in the region of the Boucle du Mouhoun in Burkina Faso. A preliminary cross-sectional survey allowed the identification of the 10 villages with the highest parasitological prevalences (from 2.1% to 16.1%). In each of these 10 villages, two herds of approximately 50 bovines were selected, one being treated with ISM (1mg/kg b.w.) and the other remaining untreated as control group. All animals (treated and untreated herds) becoming infected were treated with DA (3.5mg/kg b.w.). In total, 978 head of cattle were followed up. Fortnightly controls of the parasitaemia and PCV were carried out during 8 weeks. The main trypanosome species was Trypanosoma vivax (83.6%) followed by Trypanosoma congolense (16.4%). In two villages, less than 25% of the control untreated cattle became positive indicating no need to use prophylactic treatment. These two villages were not further studied. Resistance to ISM was observed in 5 of the remaining 8 villages (Débé, Bendougou, Kangotenga, Mou and Laro) where the relative risk (control/treated hazard ratios) of becoming infected was lower than 2 i.e. between 0.89 (95% CI: 0.43-2.74) and 1.75 (95% CI: 0.57-5.37). In contrast, this study did not show evidence of resistance to DA in the surveyed villages with only 8.6% (n=93) of the cattle relapsing after treatment. Our results suggest that because of the low prevalence of multiple resistances in the area a meticulous use of the sanative pair system would constitute the best option to delay as much as possible the spread of chemoresistance till complete eradication of the disease by vector control operations.     

Lectin histochemical investigations of the distal gut of chicks with special emphasis on the follicle-associated epithelium

Carbohydrates on epithelial cell surfaces play an important role as attachment sites for different microorganisms like bacteria, viruses and protozoa. To obtain more information about the distribution of carbohydrates on the luminal surface along the intestine, lectin histochemical studies on different gut segments of chicks of different age groups were carried out using a panel of 13 lectins with specificities for Man, Glc, Gal, GalNAc, GlcNAc or GlcNAc oligosaccharides and Sia. Furthermore, we tried to find out whether previously reported specificities of certain lectins for M cells (membranous or multifold cells) in the bursa of Fabricius (BF) can be observed also on M cells of the intestine. As a result we were able to demonstrate binding of all lectins employed in these studies in all investigated gut segments. In some cases, the application of the same lectin led to varying staining intensities of the same histological structures in different age-groups (e.g. staining of the brush border with WGA, LEA, MAA or Conarva) or different gut segments (e.g. staining of goblet cells with CMA II, LEA and MPA). Hence, terminal carbohydrate residues of glycoconjugates on the intestinal epithelium vary depending on age and organ site. As glycoconjugates can act as attachment sites for microorganisms, these differences in the distribution of sugar residues may be one explanation for the site-specificity of certain pathogens. Furthermore, the binding of lectins to the follicle-associated epithelium (FAE) of the BF differs from that to the FAE of the intestine again stressing the site specificity of lectin binding. Thus, up to now no universal M-cell marker along the chicken intestine exists.     

Duration of colostral antibodies to bovine leukemia virus by two serologic tests

The duration of detectable colostral antibodies to the glycoprotein antigen of bovine leukemia virus was studied in calves which were born to bovine leukemia virus-infected cows, but showed no serologic evidence of prenatal infection. Colostral antibodies detectable by an agar-gel immunodiffusion test (AGIT) persisted for less than 1 month to 6 months (mean 2.9 months) in the 139 calves examined. Colostral antibodies were detectable 1 to 5 months longer by radioimmunoprecipitation assay than by the AGIT in 22 of the 24 calves studied comparatively. The mean duration of colostral antibodies in those 24 calves was 3.8 months (min-max, 2 to 6 months) for the AGIT and 6.0 months (min-max, 4 to 9 months) for the radioimmunoprecipitation assay.     

Nutritional interventions to prevent and rear low‐birthweight piglets

Selection for hyperprolific sows, as a means of increasing litter size and profit, has resulted in an increased number of low‐birthweight (LBW) piglets. These LBW piglets might suffer from increased morbidity and mortality during the early neonatal period. In addition, they show reduced growth performance, meat and carcass quality, which leads to an important economic loss for the farmer in the post‐natal period. Therefore, nutritional interventions can be undertaken to prevent and rear LBW piglets. In the first part of this review, the preventive strategies at the sow level will be discussed. Approaches in preventing LBW piglets are to optimize the intrauterine environment via supplementing the sow during gestation. In the second part of this review, the interventions at the piglet level will be described. To increase the survival and growth rates of LBW piglets, one must focus on ensuring adequate colostrum and milk intake. Interventions include supplementing piglets, split nursing, split weaning and cross‐fostering. Additional interventions increasing the probability of optimal post‐natal food intake will be discussed.     

The detection of obligate anaerobic bacteria in udder secretions of dry cattle with mastitis during summer: a comparison between gas-liquid chromatography and bacteriological culturing methods

Udder secretions sampled during the summer in 1984 and 1985 from mastitic quarters of 51 non-lactating cattle, mainly heifers less than 2 years of age, were examined bacteriologically for the presence of (facultative) aerobic and obligate anaerobic bacteria (OAB) and by gas-liquid chromatography (GLC) in order to detect volatile fatty acids (VFA), metabolic end-products of OAB. Forty-nine samples yielded positive cultures and in 20 cases these were mixtures of (facultative) aerobes and OAB. Only two specimens appeared to be sterile and from one specimen only were OAB cultured. Corynebacterium pyogenes was isolated from 35% of the cases and Peptococcus indolicus and Fusobacterium necrophorum from 31 and 22%, respectively. In most specimens (19/21) which yielded OAB after culturing, VFA (C3-C6) could be detected by GLC. Detection of VFA in summer mastitis secretions appeared to be a useful technique to evaluate the importance and association of OAB with summer mastitis. Because samples can be easily collected and stored at -20 degrees C, this is especially advantageous in situations where adequate facilities for the isolation of OAB are not readily available.