Comparative lipid and lipoprotein metabolism

This review summarizes a number of recent reports in several areas of lipid and lipoprotein metabolism. Absorption of dietary lipids, cholesterol synthesis, and biliary cholesterol metabolism are mentioned only briefly to be complete. Comparative aspects of lipoprotein metabolism, however, are detailed in an effort to integrate the myriad metabolic events which characterize these important lipid transport particles. Where comparative information is known, those aspects of lipoprotein metabolism that may be protective against atherogenesis in certain mammalian species are also described. Efforts to understand atherogenic resistance comparatively in animals lends a better understanding of the metabolic events leading to coronary artery disease in humans. They also provide an important basis for understanding lipid metabolism in numerous veterinary species.     

Comparison of methods to assess dog owners' therapeutic compliance

Objective To compare different methods for assessing the compliance of veterinary clients administering medication to their dogs.
Procedure Thirty-one owners whose dogs were prescribed amoxycillin-clavulanate, twice and thrice daily, for a duration of five to seven days were recruited from three Sydney veterinary hospitals. Compliance was assessed by electronic monitoring devices, return medication counts, client self-reports and veterinarians' estimation of likely compliance.
Results Electronic monitoring showed owners administered on average 84% (range 7 to 104%) of prescribed medication to their dogs. Both return medication counts and client self-reports tended to overestimate therapeutic compliance when compared with electronic monitoring. When questioned, the majority of owners (71%) claimed perfect compliance with the prescribed regimen. No correlation was found between veterinarians' estimates of owner compliance and that assessed electronically.
Conclusion Electronic monitoring provided valuable information on dose timing and variation, but proved costly and difficult to employ in veterinary practice. Simplicity and low cost of return medication counts makes this method attractive for use in veterinary compliance studies. Client self-reports reliably detected some noncompliers and permitted identification of individual problems or errors. For practical purposes a combination of return medication counts and client self-reports may have merit in future veterinary compliance studies.     

Influence of Bos indicus crossbreeding and cattle age on apparent utilization of a high-grain diet

Ten Bos indicus x MARC III (initial BW = 303 +/- 25 kg) and 10 MARC III (initial BW = 322 +/- 16 kg) steers were used in a 2 x 2 factorial design to determine whether cattle age or Bos indicus crossbreeding influence site of digestion of a high-grain diet. Initially, five Bos indicus x MARC III and five MARC III steers were fitted with duodenal cannulas and adapted to a 95% concentrate diet that was offered for ad libitum consumption for a 237-d feeding period (calves). During the feeding period, duodenal and fecal samples were collected during 4-d periods beginning on d 14, 67, 137, and 228. The remaining 10 steers were fed a forage-based diet for a targeted daily gain of .6 to .7 kg for 210 d (yearlings). Following this period, yearling steers were duodenally cannulated and adapted to the 95% concentrate diet. Yearling steers had ad libitum access to feed for 165 d, and samples were collected during 4-d periods beginning on d 13, 42, 102, and 159. Dry matter intake was 9.8 and 7.6 kg/d and daily gain was 1.35 and 1.16 kg in yearlings and calves, respectively. Apparent OM digestion in the stomach was greater (P < .01) in yearlings than in calves. In contrast, postruminal disappearance as a percentage of OM intake was greater (P = .05) in calves than in yearlings. Duodenal flows of total N, microbial N, nonmicrobial N, and total amino acids and total tract N digestibility were not affected (P > .05) by age or Bos indicus crossbreeding. Fecal N excretion was greater (P < .01) in yearlings than in calves. Results of this experiment suggest little effect of Bos indicus influence on utilization of a high-grain diet. However, more feed is digested in the rumen of yearlings than of calves consuming a high-grain diet.     

Butorphanol and azaperone as a safe alternative for repeated chemical restraint in captive white rhinoceros (Ceratotherium simum).

Anesthesia in the white rhinoceros (Ceratotherium simum) has routinely involved potent narcotic anesthetic agents such as etorphine or carfentanil with their associated adverse side effects. In captive rhinoceroses conditioned to routine handling, a combination of butorphanol and azaperone at mean (+/- SD) doses of 69.3 +/- 18.0 mg and 103.1 +/- 20.9 mg, respectively, was used to produce levels of neuroleptanalgesia ranging from light "standing" sedation to deeper planes of anesthesia producing sternal and lateral recumbency. This combination was used for repeated (minimum repeat frequency of 3 days between events) anesthetic episodes (n = 26) in two animals, with the remaining episode performed in a white rhinoceros with chronic renal disease. The action of butorphanol was satisfactorily reversed with naltrexone (125 mg i.v. and 125 mg i.m.). Results (mean +/- SD) include sternal recumbency achieved in 14.1 +/- 8.1 min after i.m. dosing, standing and ambulation occurred in 1.7 +/- 0.6 min after reversal, heart rate was 62.0 +/- 10.1 beats/min, respiratory rate was 14.7 +/- 5.6 breaths/min, and percentage of oxygen saturation of hemoglobin (Spo2) was 89.2 +/- 3.0%. Without supplementation, the total elapsed time ranged from 44.9 min to 103.0 min, whereas elapsed times up to 214.3 min were achieved with supplementation (mean time to supplementation was 28.0 +/- 13.9 min after initial dosing). Butorphanol and azaperone produced adequate muscle relaxation and apparently adequate analgesia for minor surgical interferences, including abdominal laparoscopy. Respiratory rates and Spo2 measurements were improved compared with reports of using more potent opioids in this species.     

Intralesional cisplatin chemotherapy and topical cryotherapy for the control of choanal squamous cell carcinoma in an African penguin (Spheniscus demersus).

A 3.5-yr-old, 2.5-kg female African penguin (Spheniscus demersus) was diagnosed with a choanal squamous cell carcinoma on the basis of biopsy after a history of choanal ulceration and anorexia with weight loss. Therapeutic modalities included the use of intralesional cisplatin followed by localized, topical cryotherapy with liquid nitrogen. The penguin remained free of clinical disease for a period of 9 mo, at which time a second cryotreatment was performed. The patient has remained free of all signs of choanal carcinoma for a period of 13 mo since the second cryotreatment.     

Kisspeptin,c‐Fos and CRFR Type 2 Co‐expression in the Hypothalamus after Insulin‐Induced Hypoglycaemia

Normal reproductive function is dependent upon availability of glucose and insulin‐induced hypoglycaemia is a metabolic stressor known to disrupt the ovine oestrous cycle. We have recently shown that IIH has the ability to delay the LH surge of intact ewes. In the present study, we examined brain tissue to determine: (i) which hypothalamic regions are activated with respect to IIH and (ii) the effect of IIH on kisspeptin cell activation and CRFR type 2 immunoreactivity, all of which may be involved in disruptive mechanisms. Follicular phases were synchronized with progesterone vaginal pessaries and at 28 h after progesterone withdrawal (PW), animals received saline (n = 6) or insulin (4 IU/kg; n = 5) and were subsequently killed at 31 h after PW (i.e., 3 h after insulin administration). Peripheral hormone concentrations were evaluated, and hypothalamic sections were immunostained for either kisspeptin and c‐Fos (a marker of neuronal activation) or CRFR type 2. Within 3 h of treatment, cortisol concentrations had increased whereas plasma oestradiol concentrations decreased in peripheral plasma (p < 0.05 for both). In the arcuate nucleus (ARC), insulin‐treated ewes had an increased expression of c‐Fos. Furthermore, the percentage of kisspeptin cells co‐expressing c‐Fos increased in the ARC (from 11 to 51%; p < 0.05), but there was no change in the medial pre‐optic area (mPOA; 14 vs 19%). CRFR type 2 expression in the lower part of the ARC and the median eminence was not altered by insulin treatment. Thus, disruption of the LH surge after IIH in the follicular phase is not associated with decreased kisspeptin cell activation or an increase in CRFR type 2 in the ARC but may involve other cell types located in the ARC nucleus which are activated in response to IIH.     

Genetic divergence of kingfish from Japan, Australia and New Zealand inferred by microsatellite DNA and mitochondrial DNA control region markers

ABSTRACT: Genetic polymorphism in kingfish, collected from coastal waters of Japan, Australia and New Zealand, were examined using microsatellite (MS) DNA and mitochondrial DNA (mtDNA) control region markers. Sixteen to 25.7 alleles per locus were observed in three MS markers, while the average observed (and expected) heterozygosities were 0.782 (0.918), 0.750 (0.809) and 0.650 (0.888) for Australian, Japanese and New Zealand kingfish, respectively. Twelve mtDNA haplotypes were detected by the digestion of control region sequences with five endonucleases: Hae III, Hinf I Mbo I, Rsa I and Taq I. Significant genetic divergence was observed between the kingfish population from Japan and those from Australia–New Zealand. There was no significant differentiation among the Australian and New Zealand population samples.     

Level of nutrition and splanchnic metabolite flux in young lambs

Splanchnic metabolite flux was measured in young lambs given access to a high-concentrate diet either ad libitum (ADLIB) or at a maintenance level (MAINT) for 21 d. Net fluxes of urea N (UN), ammonia N (NH3 N), alpha-amino N (AAN), amino acids, glucose (G), and lactate (L) across the liver and portal-drained viscera (PDV) were measured in 11 crossbred ram lambs (35 kg) surgically fitted with indwelling catheters in the portal, hepatic, and mesenteric veins and mesenteric artery. During the 21-d period, daily N and ME intakes were 24.6 and 10.7 g N/d and 3.02 and 1.28 Mcal/d, respectively, for ADLIB and MAINT lambs. Intakes, thus, were 42% lower for MAINT than for ADLIB lambs. Net portal fluxes of UN, NH3 N, AAN, and L in MAINT lambs were 46%, 84%, 50%, and 74%, respectively, of that in ADLIB lambs. Expressed as a percentage of N intake, the proportion of AAN absorbed by the PDV was higher in MAINT lambs (P less than .05) than in ADLIB lambs. There was no net portal glucose absorption in either group of lambs; however, net hepatic glucose production in MAINT lambs was 48% of that in ADLIB lambs. There was net utilization of glutamine by the PDV; net glutamine flux in MAINT lambs was 49% of that in ADLIB lambs. The liver utilized AAN and NH3 N and produced UN. Splanchnic tissues modulate metabolite flux following changes in feed intake in young ruminants.     

Differences among breed crosses of cattle in the conversion of food energy to calf weight during the preweaning interval

The objective of this study was to determine whether F1 cows that differ in genetic potential for weight at maturity and milk yield vary in the conversion of food energy to calf weight gain. Food intakes and weight change data were recorded by pen for cows and calves from approximately 45 d postpartum. Cows assigned to the study were 7- to 9-yr-old F1s produced by top-crossing Angus, Hereford, Brown Swiss, Chianina, Gelbvieh; Maine Anjou, and Red Poll sires to either Angus or Hereford dams. Calves were sired by Simmentals. Experimental units were pens (10 to 12 cow/calf pairs); pen was replicated within breed of sire in each of 2 yr (n = 24). Calf weight gain and energy consumed by the dams differed among the F1s, as did the ratio of calf weight gain to energy consumed by the calf and cow. Angus or Hereford (35.8), Red Poll (35.7), or Maine Anjou (35.6) F1s produced more calf weight per unit of energy consumed (g/Mcal) by the cow and calf than Chianina (33.1) or Gelbvieh (33.7) F1 females; Brown Swiss cows were intermediate (34.3). Differences in food conversion efficiency exist among breed crosses. These differences seem to be associated with breed cross differences in genetic potential for milk yield and mature weight; an exception to this trend was the Maine Anjou.