A J Lepine’s research while affiliated with Cornell University and other places

The effects of long-term athletic training are associated with excessive skeletal muscle turnover attributable to increased rates of myofibrillar protein synthesis and proteolysis, which are mechanisms poorly understood in the athletic dog. A physiologic field study using 44 English pointers and Labrador retrievers that had been purposely bred for bird hunting and retrieving was conducted to examine changes in the ubiquitin-proteasome (UP) pathway, which has been implicated in exercise-induced proteolysis. Muscle biopsy samples were collected from all dogs in September (preseason, pretraining) and February (peak season, peak activity). Western blot analysis was used to assess changes in expression of various components of the UP pathway in the biopsy samples. Citrate synthase and glycogen levels were also measured in a subset of these samples. Results across the population indicated pronounced up-regulation of ubiquitinated conjugates and the p31 regulatory capping subunit during the peak hunting period compared with the preseason period. In contrast, the catalytic core of the proteasome (beta-subunits) showed no apparent up-regulation in response to increased physical activity. Increased physical activity during the hunting season was associated with increased muscle glycogen levels and citrate synthase activity in these dogs. Overall, up-regulation of specific components of the UP pathway was an indication that it plays a role in the proteolytic process associated with skeletal muscle turnover during long-term athletic training, as previously believed.

A study was conducted to evaluate the influence of diet on hunting performance of English pointers during the quail-hunting season in southwest Georgia. Twenty-three trained dogs were assigned to two commercially available diets (i.e., Diet A = Eukanuba Premium Performance Formula, The Iams Company, Lewisburg, OH; Diet B = Diamond Premium Adult Dog Food, Diamond Pet Foods, Meta, MO). Results showed that dogs fed Diet A maintained or gained weight and body condition throughout the hunting season while dogs fed Diet B lost body weight and body condition (P < .05). Dogs fed Diet A demonstrated superior hunting performance (P < .05) compared with those fed Diet B based on total finds per hunt and on the number of birds located per hour of hunting. All blood variables were within normal ranges for adult healthy dogs throughout the season. These results imply that diet can affect the overall performance of hunting dogs and should provide useful information to trainers, handlers, and clinicians who are concerned with promoting the best performance and health in hunting dogs and other canine athletes.

Two milk replacers (MR) were analyzed for fatty (FAP) and amino (AAP) acid profiles and compared to bitch milk (CTL). To examine the effect of diet on serum FAP and AAP, 40 colony bred Beagle puppies from 7 litters were randomly assigned to three treatments (TRT), CTL (n = 15), MR-I (n = 14) or MR-II (n = 11). All puppies were allowed to nurse the dam for 24 h with subsequent MR feedings every 3 h for d 1-2 and gradually increased to every 6 h over the duration of the study. While both MR diets met AAFCO requirements for growth, MR-I was formulated for 40% protein and 30% fat compared to MR-II at 33% protein and 40% fat. MR-I was found to reflect CTL milk FAP more closely than MR-II, particulary palmitic, stearic, oleic, arachidonic (AA) and decosahexaenoic (DHA) acids (P < 0.05). Milk FAP were reflective of serum FAP, with MR-I fed puppies more closely matching CTL fed puppies in FAP, particulary palmitic, oleic, AA and DHA (P < 0.05). MR-I contained higher levels of essential (EAA) and non-essential (NAA) amino acids than MR-II. Puppies fed MR-I were more similar to CTL in serum EAA (P < 0.05) and EAA:NAA ratio (P < 0.05). Data indicate that serum FAP and AAP of growing puppies can be influenced by and are reflective of MR formulation .

Forty colony bred Beagle puppies from 7 litters were randomly assigned to three treatments (TRT) and monitored for growth and body composition (BC) as determined using DEXA at d 30 of age. The TRT were dam reared (CTL; n = 15), canine milk replacer (MR)-I (n = 14) and MR-II ( n = 11). All puppies were allowed to nurse the dam for 24 h. MR TRT were subsequently fed every 3 h and decreased to 4 feedings/day for the remainder of the study (d 30). While both MR diets met AAFCO requirements for growth, MR-I was formulated with fat and protein sources to more closely reflect bitch milk fatty acid (FAP) and amino acid (AAP) profiles. No differences were detected in intake between the MR puppies, however, puppies fed MR-I had increased average daily gain and gain efficiency than MR-II fed pups (P < .05). Both MR groups had higher (P < .05) daily gains than did the CTL pups, although this is probably due to unlimited intake by the MR TRTs. BC of puppies fed MR-I did not differ from CTL pups in body fat percentage (BF), but was higher (P < .01) in lean tissue (LT) than both CTL and MR-II. Puppies fed MR-II were found to have the highest BF (P < .01) and lowest LT (P < .05). MR formulation more similar to bitch milk in FAP and AAP results in enhanced structural tissue growth indicating an improved nutritional status in neonatal puppies.

Thirty-nine Great Dane puppies from 5 litters were studied from 2 through 12 months of age Puppies were divided into three groups and fed diets identical in protein and fat (27% and 14% respectively), but differing in calcium and phosphorus. The diets consisted of 0.48% Ca: 0.4% P (Low) (n=12), 0.8% Ca: 0.67% P (Med) (n=12), or 2.7% Ca: 2.2% P (High) (n=15) Nursing pups were supplemented with specific diets as they began to wean at 5-6 weeks A Lunar, model DPX-L densitometer (DEXA) was used to evaluate dogs monthly until 8 months and bimonthly thereafter Lean body mass, fat tissue and body weight of puppies were nearly identical at 8 weeks, but dietary mineral differences were already reflected in bone mineral density (BMD), 0.4421 g/cm2 ± .0074, 0.4555 g/cm2 ± 0.0174 and 04819 g/cm2 ± 0.0276 for Low, Med and High groups respectively. Differences continued through 6 months, after which they diminished. BMD at 12 months was 0 9756 g/cm2 ± 0.0766, 1.046 g/cm2 ± 0.0648 and 1.0528 g/cm2 ± 0.0725 respectively. Mineral intake as early as 5 weeks of age is rapidly reflected in the BMD of developing puppies.

Two experiments were conducted, one with weanling pigs (n = 288) and the second with grower-finisher swine (n = 216), to evaluate the efficacy of dietary vitamin C on various performance and serum measurements. Magnesium-L-ascorbyl-2-phosphate (46% L-ascorbic acid) served as the vitamin C source and was incorporated at dietary levels of 0, 50, or 500 ppm in both experiments. Pigs were allotted by sex, weight, and litter to randomized complete block designs. The nursery trial was conducted at four time periods and contained 12 replicates, whereas the grower-finisher experiment was over four time periods and contained nine replicates. Blood samples were collected initially from nine randomly selected pigs in both experiments, and from each pig within each pen at 2 and 5 wk postweaning, and at the 4- and 8-wk period in the grower-finisher trial. A killed Salmonella typhinurium bacterin was injected i.m. into starter pigs at 2 wk postweaning and at wk 4 and 6 in grower-finisher pigs. Hemagglutination titers were evaluated at 5 wk with the nursery pigs and at the 8-wk period with the grower-finisher swine. At the end of the grower-finisher trial, liver and kidney tissue were analyzed for ascorbate. Starter pigs grew faster (P < .05) and had improved gain:feed ratios (P < .05) when vitamin C was provided during the first 2 wk postweaning, but not during the latter 3-wk period. There was no improvement in pig gain or feed efficiency to vitamin C supplementation during any phase of the grower-finisher period.(ABSTRACT TRUNCATED AT 250 WORDS)

A total of 24 crossbred barrows were used in a 19-d metabolism trial to determine the effect of dietary structured triacylglycerides synthesized by the random reesterification of medium-chain triacylglycerides (MCT) and menhaden oil on growth performance, nitrogen retention, and apparent digestibilities of nitrogen, lipid, and fatty acids. Pigs were randomly assigned to four dietary treatments differing only in lipid source. Dietary treatments (percentage by weight of total lipid) contained either 1) corn oil: soybean oil:MCT oil (40:10:50), 2) MCT oil:menhaden oil (60:40 as structured triacylglyceride), 3) MCT oil: menhaden oil (60:40 nonstructured, physical mixture), or 4) structured triacylglyceride (as in 2): safflower oil:canola oil (80:10:10). Total fecal and urine collections were conducted during two 5-d periods. Apparent nitrogen digestibility and nitrogen retention were high (> 95%) and not affected (P > .05) by dietary treatment. Apparent fatty acid digestibilities were affected by dietary lipid source. Palmitic and arachidonic acid digestibilities were lower (P < .05) for Diet 1, heptadecanoic acid digestibility was elevated by 21% (P < .05) for Diet 2 relative to Diet 3, and stearic acid digestibility was highest (P < .05) for Diet 1, followed by Diets 2, 3, and 4 in decreasing order. This study demonstrates that the physical nature of the lipid (structured vs nonstructured) affects fatty acid digestibility patterns in the growing pig. Further evaluation of MCT/menhaden oil structured triacylglyceride is needed.

The effects of supplementation of dietary clofibric acid (.5% wt/wt) on fatty acid binding protein (FABP) activity, apparent lipid digestibility, and serum cholesterol concentrations were evaluated in weanling pigs. Twenty-four barrows were allotted by weight and litter to a randomized complete block design with two treatments (basal vs clofibric acid) in six replicates. Nutrient digestibility measurements were made for a 2-wk period, after which the pigs were killed and tissues were collected. No differences in BW, liver, proximal small intestine, distal small intestine, and proximal and distal intestinal mucosa weights were observed. Apparent lipid digestibility was greater (P < .05) for the overall 2-wk period in clofibric acid-supplemented pigs (81.5 vs 76.6%). This paralleled the increased FABP activity in the distal small intestine (P < .001) of clofibric acid-supplemented pigs. Proximal intestine and liver FABP activities were unaffected by dietary treatment. Serum cholesterol concentrations were markedly lowered by clofibric acid supplementation. During wk 1, pigs fed the basal diet had twofold greater (P < .01) serum cholesterol concentrations, whereas during wk 2, basal-fed pigs had fourfold greater (P < .01) serum cholesterol concentrations (81.5 vs 18.3 mg/dL). These results suggest that elevated intestinal FABP activities may augment fatty acid absorption from the gastrointestinal tract.

Twenty-four growing pigs (18.3 kg body weight) were used in 19-day metabolism trial to determine the effect of n-3/medium-chain triacylglyceride (MCT)-structured triacylglyceride on plasma and tissue lipid profiles. Pigs were allotted to four liquid diets, each providing 19.5% protein (dry matter basis) as Na- and Ca-caseinate + soybean protein isolate. Lipid composition (percentage by weight of total lipid) by treatment was as follows: (I) corn oil:soybean oil:MCT oil (40:10:50), (II) MCT oil:menhaden oil (60:40 as structured triacylglyceride), (III) MCT oil:menhaden oil (60:40 non-structured, physical mixture), and (IV) structured triacylglyceride (as in II):safflower oil:canola oil (80:10:10). Blood samples were obtained on days 0, 12, and 19 with liver and muscle samples obtained on day 19. With the exception of arachidonic acid, plasma fatty acid profiles reflected dietary fatty acid profiles. Plasma arachidonic acid percentage was higher (P < 0.05) in pigs consuming diet 1 despite a lower dietary content of this fatty acid relative to diets II, III, and IV. Platelets from pigs consuming diets II or III had lower percentage linoleic and arachidonic acid percentages on day 19 compared with diet 1, which appeared to be compensated for by elevated eicosapentaenoic and docosahexaenoic acids. Diets II, III, and IV resulted in higher (P < 0.05) percentages of myristic, pentadecenoic, palmitic, palmitoleic, heptadecanoic, heptadecenoic, stearic, linoleic, eicosapentaenoic, docosahexaenoic, and nervonic acids in the liver and elevated (P < 0.05) myristic, palmitic, palmitoleic, stearic, linoleic, and eicosapentaenoic acids in the muscle. Physical form (structured versus non-structured triacylglyceride) did not affect fatty acid profiles.

A 2 x 3 factorial experiment in a randomized complete block design was conducted using a total of 180 weanling pigs in five replicates. The study evaluated the efficacy of two dietary vitamin E sources (D-alpha-tocopherol, DL-alpha-tocopheryl acetate) added at three dietary levels (16, 48, 96 IU/kg) during a 35-d postweaning trial. Pigs within each treatment were fed two similarly fortified vitamin E diets in sequence; the first contained 40% milk products and was fed to 14 d, and the second contained 20% milk product and 5% fat and was provided from 15 to 35 d postweaning. Five pigs per pen per replicate were bled weekly for serum analysis of alpha-tocopherol, Se, cholesterol, triglyceride, and glutathione peroxidase (GSH-Px) activity. At the end of the trial, one pig per pen was randomly selected and killed with liver, loin, lung, and heart excised and frozen for tocopherol analysis. Postweaning gains, feed intakes, and efficiencies were similar between the two vitamin E sources and at the various dietary levels. Serum tocopherol concentrations were consistently higher when D-alpha-tocopherol was provided. Vitamin E sources and levels had no effect nor did they influence weekly serum Se, cholesterol, or triglyceride concentrations or GSH-Px activity. A serum and tissue interaction (P less than .05) response occurred between dietary vitamin E source x level with alpha-tocopherol concentrations increasing linearly (P less than .01) as dietary vitamin E level increased, but at a higher rate when D-alpha-tocopherol than when DL-alpha-tocopheryl acetate as fed.(ABSTRACT TRUNCATED AT 250 WORDS)