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Biomedical subjects

R Butterwick

Publications and source records attributed to R Butterwick.

8 recordsLinked to original sources

A rapid screening technique for feline odontoclastic resorptive lesions.

The feline odontoclastic resorptive lesion (FORL) status (presence or absence of odontoclastic resorptive lesions) of 423 clinically healthy cats was determined based on radiographic findings in a series of full mouth radiographs (eight views). This status was compared with the FORL status based on evaluation of only two views, namely the right and left mandibular premolar and molar views. Using the FORL status of the right and left third mandibular premolars (307 and 407) alone correctly predicted overall FORL status in 93.4 per cent of cats. The sensitivity of the new technique (FORL cases correctly diagnosed as positive by the test) was 78.5 per cent, while the negative predictive value (negative FORL cases correctly diagnosed by the test) was 91.3 per cent. Overall FORL status can therefore be confidently diagnosed in nine out of 10 cats by assessing FORL status in just two teeth (307 and 407) using two films, which has benefits for the cat (less anaesthetic time and reduced exposure to radiation) and the owner (reduced cost of screening).

Animals↗

Energetics and litter size variation in domestic dog Canis familiaris breeds of two sizes.

We measured resting metabolic rate (RMR), daily energy expenditure (DEE) and metabolisable energy intake (MEI) in two breeds of dog during peak lactation to test whether litter size differences were a likely consequence of allometric variation in energetics. RMR of Labrador retrievers (30 kg, n=12) and miniature Schnauzers (6 kg, n=4) averaged 3437 and 1062 kJ/day, respectively. DEE of Labradors (n=6) and Schnauzers (n=4) averaged 9808 and 2619 kJ/day, respectively. MEI of Labradors (n=12) was 22448 kJ/day and of Schnauzers (n=7) was 5382 kJ/day. DEE of Labrador pups (2.13 kg, n=19) was 974 kJ/day and Schnauzers (0.89 kg, n=7) were 490 kJ/day. Although Labradors had higher MEIs than Schnauzers during peak lactation, there was no difference in mass-specific energy expenditure between the two breeds. Hence, it is unlikely that litter size variation is a likely consequence of differences in maternal energy expenditure. Individual offspring were relatively more costly for mothers of the smaller breed to produce. Therefore, litter size variations were consistent with the expectation that smaller offspring should be more costly for mothers, but not that smaller mothers should per se invest more resources in reproduction.

Animals↗

Validation of dual energy X-ray absorptiometry (DXA) by comparison with chemical analysis of dogs and cats.

BACKGROUND: Dual-energy X-ray absorptiometry (DXA) has been used extensively to measure body composition, but has been validated by comparison to chemical analysis on relatively few occasions. Moreover, these previous validation studies have ground up entire carcasses prior to chemical analysis, thus potentially obscuring sources of error in the DXA analysis. OBJECTIVE: The purpose of this study was to validate DXA by comparison to chemical analysis in dogs and cats, performing chemical analysis on dissected rather than ground carcasses to reveal sources of discrepancy between the two methods. DESIGN: Sixteen animals (10 cats and 6 dogs weighing between 1.8 and 22.1 kg) were scanned by DXA post-mortem using a Hologic QDR-1000 W pencil beam machine and then dissected into 22 separate components. Individual tissues were dried and then sub-sampled for analysis of fat content by Soxholet extraction, or ashing in a muffle furnace. Body composition by DXA was compared to body composition by chemical analysis and discrepancies between the two correlated with chemical composition of individual tissues. We also explored the capability of the machine to establish the fat contents of mixtures of ground beef, lard and water. RESULTS: DXA estimates were strongly correlated with estimates derived from chemical analysis: total body mass (r=1.00), lean tissue mass (r=0.999), body water content (r=0.992) and fat mass (r=0.982). Across individuals the absolute and percentage discrepancies were also small: total body mass (13.2 g, 1.02%), lean tissue mass (119.4 g, 2.64%), water content (101 g, 1.57%) and fat content (28.5 g, 2.04%), where the percentage error is expressed relative to the average mass of that component across all individuals. Although on average DXA compared very well to chemical analysis, individual errors were much greater. Individual errors in the lean tissue and fat tissue components were strongly correlated with the fat content of skeletal muscle and the lean content of mesenteric fat. The error in the DXA estimate of total fat content was related to skeletal muscle hydration. Experimental studies using mixtures of lean ground beef, water and lard indicated that tissue hydration may have important effects on the perception of tissue fat content by DXA. Bone mineral content by DXA was approximately 30% lower than whole body ash content but only 7.7% lower than ash content of the bones. CONCLUSIONS: On average pencil beam DXA analysis using the Hologic QDR-1000 W machine provides an accurate estimate of body composition in subjects weighing between 1.8 and 22.1 kg. Individual discrepancies, however, can be large and appear to be related to lean tissue hydration.

Absorptiometry, Photon↗

Calculation of gross energy in pet foods: new data on heat combustion and fibre analysis in a selection of foods for dogs and cats.

Seven pectin samples, six galactomannan sources, five carrageen samples, four alginate samples, one sample of gum traganth, agar agar and gum arabicum, two xanthan samples, two inulin samples and a galacto oligosaccharide, 22 cellulose samples, six lignin samples, four starch samples, nine protein samples, six isolated fats, three meat samples, two lung samples, two samples of skimmed milk powder, 12 prepared complete dry dog foods, 21 moist dog foods, nine dry and 25 moist cat foods and 10 faecal samples were analysed for heat combustion (adiabatic bomb calorimetry), crude nutrients, acid detergent fibre (ADF), and acid detergent lignin (ADL). Some of the non-starch polysaccharides which gave low levels of crude fibre and ADF were also analysed for total, insoluble and soluble fibre. The heat combustion of cellulose ranged between 17.0 and 17.5 kJ/g organic matter (OM). The variation was somewhat larger for other non-starch polysaccharides (pectin, galactomannan sources, carageen, alginate, gums, xanthan, inulin) where heat combustion ranged between 14.0 and 18.2 kJ/g OM. The heat combustion of lignin averaged 25.5 kJ/g OM with considerable variation (17.0-29.2 kJ/g OM). Starch had a narrow range (17.2-17.3 kJ/g OM). Heat combustion of protein samples varied between 22.0 and 24.6 kJ/g, and of fat samples varied between 38.0 and 39.6 kJ/g OM. When cellulose was analysed for crude fibre only between 62 and 85% OM was detected. ADF analyses of cellulose ranged between 75 and 93% OM. The crude fibre content of all other non-starch polysaccharides did not exceed 13% OM, with the exception of pectins (ADF 0.7-37% OM) and alginates (ADF 39-66% OM), the ADF content was also below 13% in these samples. In contrast the total fibre content was above 80% OM in all non-starch noncellulose polysaccharides and the percentage of soluble fibre was high (25-93% OM). Unprocessed lignin gave high readings for crude fibre (39-61% OM) and ADF (96-99% OM), while processed lignin had low crude fibre content (< 1% OM) and low ADF content (< 32%). ADL determined unprocessed lignin (78-91% OM), but again processed lignin was analysed incompletely (< 29%). Pectin and alginate gave false positive ADL readings of up to 31% OM, while all other non-starch polysaccharides were not determined by ADL. When gross energy was calculated with the factors (kJ/g) 24 for protein, 38 for fat and 17 for all carbohydrate, including fibre, there was a good correlation between calculated gross energy and heat combustion in 67 pet foods as well as in meat, lung and skimmed milk powder. In contrast to this the same factors underestimated heat combustion of faeces by around 8%.

Animal Feed↗

Energetics of lactation in domestic dog (Canis familiaris) breeds of two sizes.

The energetics of lactation was measured in two breeds of domestic dog during peak lactation. Labrador Retrievers (30 kg) had larger litter sizes than Miniature Schnauzers (6 kg). During the 7-day experimental period, Labrador pups increased more in mass than Schnauzer pups, both absolutely and relatively. Consequently, the energy demands of the litter, relative to maternal metabolism, were higher in Labradors than Schnauzers. Milk composition and gross efficiency of milk production were not significantly different between breeds and the costs of lactation were fuelled by increases in food intake. Metabolisable energy intake was higher than predicted in Labradors, but lower than predicted in Schnauzers. These patterns differ from interspecific expectations, which would predict larger animals to reproduce more slowly, have smaller litter sizes, and invest less energy in reproduction.

Animals↗

Serum insulin-like growth factor (IGF)-I concentrations are reduced by short-term dietary restriction and restored by refeeding in domestic cats (Felis catus).

Nutritional modulation of insulin-like growth factors (IGF) and their binding proteins (IGFBP) is well established. The effect of nutritional restriction on the serum IGF/IGFBP system of adult cats was investigated to evaluate serum IGF-I as a biochemical marker of nutritional status. Assays for measuring feline serum IGF and IGFBP were validated and normal ranges established in a study population of 46 healthy nonobese adult cats. Serum concentrations of IGF-I and IGF-II correlated significantly with body weight (r = 0.75, P < 0. 0001 and r = 0.34, P < 0.03, respectively). Serum IGFBP profiles were similar to other species, including humans, dogs and guinea pigs. IGFBP-3 was the predominant binding protein reflecting IGF-I concentrations and body size. Serum IGFBP-2 concentrations were high relative to the normal human serum pool (NHS) control. Food withdrawal for 18 h followed by refeeding did not alter circulating IGF or IGFBP concentrations, including IGFBP-1, in nine cats. Short-term dietary restriction of nine adult cats to supply initially 56% (56%M) and then 42.5% (42.5%M) of calculated maintenance energy requirements for 14 d resulted in a significant weight loss (P < 0.01). However, serum IGF-I concentrations fell significantly (-51%, P < 0.01) only with 42.5%M restriction. Serum IGF-II, IGFBP, insulin and albumin concentrations were not altered during the study. We conclude that nutrition does modulate the adult feline IGF/IGFBP system, but to a lesser extent than in other species. Further evaluation is required before serum IGF-I can be used for the assessment of nutritional status in adult cats.

Animals↗

Nutritional modulation of canine insulin-like growth factors and their binding proteins.

The response of canine insulin-like growth factors (IGFs) and IGF-binding proteins (IGFBPs) to moderate nutritional restriction followed by refeeding has not previously been studied in detail. The purpose of these studies was to examine the effects of nutritional restriction on the IGF system of adult dogs. Normal serum IGF values were established after validation of heterologous RIAs for measuring canine IGFs-I and -II. Canine serum IGFBP profiles were examined by Western ligand blotting (WLB), using radiolabelled recombinant human (rh) IGF-I as the ligand, and were found to be similar to those of other species. IGF-I and IGFBP-3 concentrations correlated with body weight, thus reflecting breed size as previously shown, whereas IGF-II concentrations did not. IGFBP-2 serum concentrations and band intensity on WLB were increased compared with normal human serum IGFBP-2. Overnight fasting had no effect on IGF or IGFBP concentrations, including IGFBP-1, nor did refeeding. Prolonged restriction to 56% and then 42.5% of maintenance energy requirements for 2 weeks decreased IGF-I concentrations by 20.4% and 32.7% respectively. Feeding of the same diet ad libitum for 2 weeks normalised IGF-I concentrations. There were no changes in IGF-II or insulin levels. Serum IGFBP-2 concentrations increased with 56% restriction of maintenance energy (P = 0.03). We conclude that serum IGF-I is potentially a useful marker of short-term change in nutritional status in the adult dog.

Animals↗