Marianne Diez

Liver lipid metabolism.

The liver plays a key role in lipid metabolism. Depending on species it is, more or less, the hub of fatty acid synthesis and lipid circulation through lipoprotein synthesis. Eventually the accumulation of lipid droplets into the hepatocytes results in hepatic steatosis, which may develop as a consequence of multiple dysfunctions such as alterations in beta-oxidation, very low density lipoprotein secretion, and pathways involved in the synthesis of fatty acids. In addition an increased circulating pool of non-esterified fatty acid may also to be a major determinant in the pathogenesis fatty liver disease. This review also focuses on transcription factors such as sterol-regulatory-element-binding protein-1c and peroxisome proliferator-activated receptor alpha, which promote either hepatic fatty acid synthesis or oxidation.

The influence of sugar-beet fibre, guar gum and inulin on nutrient digestibility, water consumption and plasma metabolites in healthy Beagle dogs

The aim of the present study was to evaluate the effects of three fibres (sugar-beet fibre, guar gum and inulin) incorporated in the basal diet of healthy dogs at 7 per cent of dry matter (DM). Parameters examined included stool output, water consumption, nutrient digestibility and fasting and postprandial plasma metabolites. All fibres increased wet faecal output; an increase in faecal DM output being observed with sugar-beet fibre only. Sugar-beet fibre and inulin increased daily water consumption. Sugar-beet fibre and guar gum decreased DM digestibility. The three fibres diminished organic matter and crude protein digestibility while ether extract digestibility was decreased by guar gum and inulin. Guar gum induced lower postprandial insulin, alpha-amino-nitrogen and urea plasma concentrations. Guar gum also lowered fasting cholesterolaemia. Sugar-beet fibre and inulin showed no metabolic effects. These physiological properties suggest that guar gum would be a suitable ingredient for dietary therapy of chronic diseases such as diabetes mellitus or hyperlipidaemia in the dog.

Effects of obesity on lung function and airway reactivity in healthy dogs.

The present study investigated the effects of bodyweight (BW) gain on respiratory function and airway responsiveness in healthy Beagles using barometric whole body plethysmography (BWBP). Six adult dogs were examined before and after a fattening diet. The high-energy diet induced a mean increase in BW of 41±6%. BWBP basal parameters were recorded prior to airway reactivity testing (using increasing concentrations of histamine nebulisations). An airway responsiveness index (H-Penh300) was calculated as the histamine concentration necessary to reach 300% of basal enhanced pause (Penh, bronchoconstriction index). The same dogs underwent a doxapram hydrochloride (Dxp) stimulation testing 2 weeks later. Basal measurements showed that obese dogs had tidal volume per kg (TV/BW) that was significantly decreased whilst respiratory rate (RR) increased significantly. H-Penh300 decreased significantly in obese Beagles, indicating increased bronchoreactivity. Dxp administration induced a significant increase in TV/BW, minute volume per kg (MV/BW), peak inspiratory and expiratory flows per kg (PIF/BW and PEF/BW) in both normal and obese dogs although the TV/BW increase was significantly less marked in the obese group. In conclusion, obesity induced changes in basal respiratory parameters, increased bronchoreactivity and a blunted response to Dxp-induced respiratory stimulation. This combination of basal respiratory parameters, bronchoreactivity testing and pharmacological stimulation testing using non-invasive BWBP can help characterize pulmonary function and airway responsiveness in obese dogs.

Nitrogen balance and myofibrillar protein turnover in double muscled belgian blue bulls in relation to compensatory growth after different periods of restricted feeding

Nitrogen balance and myofibrillar protein breakdown were studied in 16 double-muscled Belgian Blue bulls during a low growth period (0.5 kg d−1) (LGP) of 4 mo (L4), 8 mo (L8), or 14 mo (L14) and the subsequent fattening period (rapid growth period, RGP). The control group (CG) was given a conventional fattening diet; the others received a low-energy, low-protein diet during LGP, and the same diet as the CG during RGP. Measurements were made halfway through the LGP, l mo after the beginning of the fattening period, and 1 mo before slaughter. Nitrogen balance was about half of CG (P < 0.001) during LGP, e.g., 50.8, 21.3, 25.8, and 23.8 g d−1, for CG, L4, L8, and L14, respectively. Between LGP and RGP, N balance increased by about 18 g N d−1 above the control in the compensating groups L4, L8 and L14. This was due to the higher digestibility and the higher metabolizability of the nitrogen in the fattening diet. Lower muscle protein accretion during the LGP resulted from decreased synthesis (P < 0.001) and de...

Influence of whole milk in diet of growing fattening Belgian Blue bulls on animal performances and on fatty acid composition in subcutaneous, intermuscular and intramuscular fats

Influence of milk in diet of growing fattening Belgian Blue bulls on animal performances and on fatty acid composition in subcutaneous, intermuscular and intramuscular fats. The use of milk as component of a fattening diet for bulls was studied in an experiment carried-out over 2 years with Belgian Blue bulls. The animals weighed 305 kg at the beginning of the experiment. In all, 15 bulls were given a control concentrate fattening diet (control group, CG), while 11 others were fed concentrate plus 6.5 to 11 1 whole milk per day according to weight or age (milk group, MG). The fattening period lasted for 174 and 181 d respectively in groups CG and MG. The MG-group had a higher killing-out percentage (P < 0.01) and the meat was characterized by a lower b∗ value and a lower dry matter content (P < 0.1). Whole milk in the diet increased the proportion of shorter chain and saturated fatty acids in fat (P < 0.001) and reduced the proportion of mono- and polyunsaturated acids (P < 0.05; P < 0.1). The extent of the changes were larger in subcutaneous and intermuscular fats than in intramuscular fat.

Study of ingredients and nutrient composition of commercially available treats for dogs

Forty-one dog treats were selected from the market with the aim of providing more insight into supplemental pet food composition. Thirty-two products (four biscuits, nine tender treats, two meat-based strips, five rawhides, eight chewable sticks, four dental care sticks) were analysed for proximate nutrient composition and quantification of minerals, hydroxyproline (Hyp), starch, glucose, fructose and sucrose. Labelled ingredients were often expressed as non-specific categories. A treat supplied a mean of 332.0±39.2 kcal metabolisable energy (ME)/100 g, and the most energy-dense product was a tender treat (475.0 kcal ME/100 g). Small dogs receive the highest percentage of maintenance energy requirement when producers’ feeding instructions are followed. Treat categories revealed variability in dry matter, crude protein, ash, Hyp and starch. Rawhides showed the highest Hyp content. Simple sugars were identified in most treats, and sucrose was the most prevalent. Results of the study suggest treat labelling should include more information on the ingredients used, and the varying nutrient and caloric density of treats should be considered. Specific attention should be given to the use of treats in dogs with specific ingredient sensitivities or nutrient considerations.