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Background Low blood 25-hydroxyvitamin D (25(OH)D) concentrations have been associated with cancer in dogs. Little research has examined what other factors may affect 25(OH)D concentrations. Objectives (1) To determine whether the presence of cancer (lymphoma, osteosarcoma, or mast cell tumor [MCT]) in dogs is associated with plasma 25(OH)D concentrations and (2) identify other factors related to plasma 25(OH)D concentrations in dogs. Animals Dogs newly diagnosed with osteosarcoma (n = 21), lymphoma (n = 27), and MCT (n = 21) presented to a tertiary referral oncology center, and healthy, client-owned dogs (n = 23). Methods An observational study design was used. Dietary vitamin D intake, sex, age, body condition score (BCS), muscle condition score (MCS), and plasma concentrations of 25(OH)D, 24,25-dihydroxyvitamin D (24,25(OH)2D) (a marker of CYP24A1 activity), as well as ionized calcium (ICa), parathyroid hormone, and parathyroid hormone-related protein concentrations were measured. An analysis of covariance was used to model plasma 25(OH)D concentrations. Results Cancer type (P = 0.004), plasma 24,25(OH)2D concentrations (P < 0.001), and plasma ICa concentrations (P = 0.047) had significant effects on plasma 25(OH)D concentrations. Effects of age, sex, body weight, BCS, MCS, and plasma PTH concentrations were not identified. A significant interaction between ICa and cancer was found (P = 0.005). Plasma 25(OH)D concentrations increased as ICa concentrations increased in dogs with cancer, whereas plasma 25(OH)D concentrations decreased as ICa concentrations increased in healthy dogs. Conclusions and Clinical Importance Results support a relationship between cancer and altered vitamin D metabolism in dogs, mediated by plasma ICa concentrations. The CYP24A1 activity and plasma ICa should be measured in studies examining plasma 25(OH)D concentrations in dogs.

Ractopamine is a synthetic catecholamine analogue which is known to affect the growth performance of both terrestrial and aquatic livestock species when it is incorporated into their feed. To investigate the effect of ractopamine on fish, rainbow trout, Oncorhynchus mykiss (Walbaum), (initial weight = 385.2 ± 1.4 g) were fed six iso-energetic (16.6 MJ kg−1) practical diets supplying two levels of ractopamine (0 and 10mgkg−1) at three levels of crude protein (CP; 25%, 35% and 45%) for 112 days. The mean weight gain (MWT), specific growth rate (SGR), condition factor (CF), viscerosomatic index (VSI), hepatosomatic index (HSI), muscle pigmentation intensity, and the proximate composition of eviscerated carcasses and viscera were measured at 28-day intervals up to day 112. There were no significant (P > 0.05) main effects of ractopamine on any of the responses measured. Significant (P & 0.05) by the inclusion of 10mgkg−1 ractopamine in the diet. These results indicate that ractopamine may not invoke the beneficial effects of enhancing protein accretion or reducing lipid content of rainbow trout when fed at 10mgkg−1 of diet at the protein levels tested.

The work described was carried out to study the expression of insulin-like growth factor 1 (IGF-1) and growth hormone-receptor (GHR) mRNA in liver, skeletal muscle and adipose tissue from three breeds of pig with varying growth characteristics. The three breeds studied were the Large Wlrite, noted for its lean tissue; the Duroc, characterized by its high intramuscular fat content; and the Meishan × Landrace (0·5 Meishan), noted for its fat, poorly conformed carcass and slower growth rate. The probes used were designed to monitor promoter usage for IGF-1 expression and also expression of the extra-cellular domain of the GHR. Eighteen gilts, six of each breed, were given a barley/wheat diet (158 g crude protein, 10·7 g lysine and 13·9 MJ energy per kg), to appetite, for 1 to 2 weeks until they reached about 85 kg. Samples of liver, longissimu s dorsi (LD) muscle and three adipose tissue depots (subcutaneous (SC), perirenal (PR) and omental (OM)) were collected immediately after slaughter and frozen in liquid nitrogen (total time of sample collection to plunging of sample into liquid nitrogen was Wliite > Meishan, with only class 1 transcripts of IGF-1 being found. GHR expression in LD muscle was lower in White than in the other tivo breeds (P = 0·022). There was a significant difference between the breeds in expression of IGF-1 mRNA (only class 1 transcripts present) in the adipose tissue (P = 0-006), the order being Wliite · Duroc · Meishan, and also a significant depot difference, with expression being highest in the SC depot (P < 0·001). There were no differences between the breeds or depots in expression of GHR mRNA in adipose tissue. The observed differences in muscle and adipose tissue IGF-1 expression may relate to the overall growth of the animal.

Belly nosing is an abnormal oral-nasal behavior that can develop to high levels in newly weaned piglets and may signal nutritional need. The effects of feed restriction on both behavior and metabolic serum parameters were examined in 128 weaned piglets. All pigs were fed ad libitum during week 1, and during week 2, half of all pens (N=8) were restricted to 65% of ad libitum intake. Blood samples were collected on days 3 and 10 after weaning and behavior was observed from video recordings on days 5 and 12. Piglets were classified as early 'nosers' or early 'non-nosers' based on their behavior on day 5. Feed restriction resulted in elevated non-esterified fatty acids (NEFA), beta-hydroxybutyrate (BHB) and both lower glucose and a NEFA/glucose ratio, but belly nosing was not affected. Piglets classified as 'nosers' did not have blood profiles indicating they were in greater nutritional need compared to 'non-nosers' in the first week of weaning, nor did they increase belly nosing or other piglet directed behaviors when restricted in week 2. Overall, no associations were found between blood parameters indicative of nutritional stress and belly nosing. This study identifies serum glucose, BHB and NEFA as well as the glucose/NEFA ratio as useful indicators of nutritional stress in newly weaned piglets.

Significant differences were found in the rates of lipogenesis, glucose oxidation and lipolysis in porcine adipose tissue from four depots; outer subcutaneous (OSC), middle subcutaneous (MSC), perirenal (PR) and omental (OM). Lipogenesis was stimulated by insulin in all depots in the order PR > OM > MSC > OSC. Lipolysis was stimulated by isoproterenol in all depots in the order PR > OM > MSC > OSC. Differences in lipid metabolism by the different depots may have an important impact on lipid accretion in vivo.

Previous studies of the porcine GH-IGF axis have demonstrated age related changes in liver, but not LD muscle, in expression of both GH-receptor (GHR) and IGF-I genes (Brameld et al, 1993; 1995), and also effects of energy availability on the expression of IGF-I in liver, but not in LD muscle (Weller et al, 1994). The work described here was carried out to study the expression of IGF-I and GHR mRNA in liver and skeletal muscle from different breeds of pig. The probes used were as described previously (Brameld et al, 1993; 1995; Weller et al, 1993; 1994), and were designed to monitor promoter usage for IGF-I expression, with the two promoters giving rise to class 1 and 2 transcripts, and also expression of the extra-cellular domain of the GH-receptor.

The total rates of heat production of fasting piglets were measured by indirect calorimetry. The glycogen contents of suckled piglets were determined and compared to fasted piglets of the same age. Total and net entry rates of glucose were measured in fasting piglets. The amounts of glucose needed to support the observed rates of energy expenditure were compared to the amounts of glycogen available for mobilization and to the metabolic utilization of glucose. The catabolism of the amino acids alanine and leucine indicated that alanine may make a substantial contribution to the energy metabolism of the piglet by direct oxidation rather than via gluconeogenesis.