OBJECTIVE To analytically validate a gas concentration of chromatography–mass spectrometry (GC-MS) method for measurement of 6 amino acids in canine serum samples and to assess the stability of each amino acid after sample storage. SAMPLES Surplus serum from 80 canine samples submitted to the Gastrointestinal Laboratory at Texas A&M University and serum samples from 12 healthy dogs. PROCEDURES GC-MS was validated to determine precision, reproducibility, limit of detection, and percentage recovery of known added concentrations of 6 amino acids in surplus serum samples. Amino acid concentrations in serum samples from healthy dogs were measured before (baseline) and after storage in various conditions. RESULTS Intra- and interassay coefficients of variation (10 replicates involving 12 pooled serum samples) were 13.4% and 16.6% for glycine, 9.3% and 12.4% for glutamic acid, 5.1% and 6.3% for methionine, 14.0% and 15.1% for tryptophan, 6.2% and 11.0% for tyrosine, and 7.4% and 12.4% for lysine, respectively. Observed-to-expected concentration ratios in dilutional parallelism tests (6 replicates involving 6 pooled serum samples) were 79.5% to 111.5% for glycine, 80.9% to 123.0% for glutamic acid, 77.8% to 111.0% for methionine, 85.2% to 98.0% for tryptophan, 79.4% to 115.0% for tyrosine, and 79.4% to 110.0% for lysine. No amino acid concentration changed significantly from baseline after serum sample storage at −80°C for ≤ 7 days. CONCLUSIONS AND CLINICAL RELEVANCE GC-MS measurement of concentration of 6 amino acids in canine serum samples yielded precise, accurate, and reproducible results. Sample storage at −80°C for 1 week had no effect on GC-MS results.

The effect of interleukin 1 (IL-1) on equine articular cartilage was investigated, using a cartilage explant culture system. Measurement of [35S]O4 incorporation revealed synthesis of matrix proteoglycan by cartilage to be decreased 45, 59.7, and 37.5% after 1, 3, and 5 days, respectively, in culture in the presence of 5 U of IL-1/ml. There was no change in proteoglycan degradation as determined by measurement of [35S]O4 release into the culture medium. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of cartilage-conditioned medium indicated that exposure of cartilage to IL-1 caused a decrease in total protein synthesis by 45, 68, and 87% after 1, 3, and 5 days, respectively, in culture while selectively inducing synthesis of the 57-kd neutral metalloproteinase stromelysin (matrix metalloproteinase-3) in young and adult horses. Identification of stromelysin was confirmed by functional characterization and immunoprecipitation. Baseline total protein synthesis, as well as specific synthesis of stromelysin in cartilage from adult and aged horses, was markedly less than that of young horses. The IL-1-induced induced reduction in total protein synthesis may not be a characteristic of equine articular cartilage from affected joints of horses with naturally acquired osteoarthritis as indicated by an overall increase in protein synthesis by osteoarthritic explants. Introduction of IL-1 into an equine articular cartilage explant culture system resulted in decrease of matrix component synthesis and increase in specific degradative enzyme synthesis and activity. Articular cartilage from aged horses had markedly less overall metabolic activity, compared with cartilage from young horses. Articular cartilage from affected joints of horses with naturally acquired osteoarthritis did not have metabolic alterations identical to those of IL-1-stimulated normal articular cartilage from the same individual, necessitating reevaluation of the validity of the IL-1-induced model of osteoarthritis. Osteoarthritis is a common, naturally acquired disease of horses, and tissue from animals of all ages and stages of osteoarthritis is available. The equine model of osteoarthritis may afford an important means of studying the alterations in articular cartilage metabolism as a function of age and disease severity.

Chronic wasting disease (CWD) is a transmissible spongiform encephalopathy (TSE) of Rocky Mountain elk in North America. Recent studies suggest that tissue and blood mineral levels may be valuable in assessing TSE infection in sheep and cattle. The objectives of this study were to examine baseline levels of copper, manganese, magnesium, zinc, selenium, and molybdenum in the brains of Rocky Mountain elk with differing prion genotypes and to assess the association of mineral levels with CWD infection. Elk with leucine at prion position 132 had significantly lower magnesium levels than elk with 2 copies of methionine. Chronic wasting disease-positive elk had significantly lower magnesium than control elk. The incorporation of manganese levels in addition to magnesium significantly refined explanatory ability, even though manganese alone was not significantly associated with CWD. This study demonstrated that mineral analysis may provide an additional disease correlate for assessing CWD risk, particularly in conjunction with genotype.

Labor and delivery stimulate increased release of catecholamines and endogenous opioid peptides in neonates. Catecholamines promote adaptation to the extrauterine environment after birth. Enkephalins are stored together with catecholamines in the adrenal medulla and have an inhibitory effect on catecholamine release. We investigated the influence of labor and neonatal hypoxia on epinephrine, norepinephrine, and met-enkephalin release in calves. Blood samples were taken from the umbilical artery before rupture of the umbilical cord and from the jugular vein repeatedly after birth. Highest plasma norepinephrine concentration was found in calves delivered at the end of gestation (term calves) before umbilical cord rupture. In calves delivered before the physiologic end of gestation (preterm calves), norepinephrine values increased after cord rupture, but remained lower than values in term calves. Epinephrine release followed a similar pattern, but norepinephrine was clearly predominant. In term calves, met-enkephalin values were significantly higher than values in preterm calves. In calves of both groups, met-enkephalin release increased after cord rupture. During birth, the increase in catecholamine release seems to take place earlier than that of enkephalins. Norepinephrine-dominated stimulation during expulsion of the calf might be followed by increasing enkephalinergic inhibition after cord rupture and onset of respiration. Reduced release of catecholamines and enkephalins in preterm calves may be connected with delayed adaptation to the extrauterine environment.

The study aimed to determine the effects of higher levels of methioninesupplementation than the recommended NRC level in the diets on the weight andhistomorphology of the bursa of Fabricius as indicators for the immune status of broilerchickens. A total of 60, one-day-old, broiler chicks were divided into 4 groups (Control, T1,T2, and T3 groups) and accommodated in separate pens at the College of AgriculturalEngineering Sciences, University of Sulaimani. The chicks were fed on a starter diet for thefirst 11, a grower diet on days 12-25 and a finisher diet on days 26-42. The methioninesupplement MethioGrow was added daily to the drinking water of the treatment groups T1, T2, and T3 by the levels 0.25, 0.50, 0.75 ml per liter respectively for 42 days, whereas thoseof the control group were provided with additives-free drinking water. On day 42, the chickswere euthanized and the bursa of Fabricius was excised, weighed by a sensitive balance and5μm thick tissue sections were obtained, stained by Hematoxylin and Eosin stains andexamined by a light microscope to examine the histological findings. The weights’ mean ofthe bursa of Fabricius on day 42 was significantly higher in groups T2 and T3 than in thecontrol group and the microscopic examination of the bursa of Fabricius revealed slightincrease in numbers of lymphocytes in the medullary region of the lymphoid follicles inchicks of the treatment groups 1 and 2 (T1 and T2) and slight increase in lymphocytes inboth the cortical and medullary regions of the lymphoid follicles in chicks of the treatmentgroup 3 (T3) in comparison with chicks of the control group. In conclusion, the obtainedresults revealed that supplementation of higher levels of methionine in the broiler diet thanthe level recommended by the NRC has positive effects on the immune status of the broilersand they support the suggestions of previous reports that referred to the insufficiency ofmethionine requirements of broiler based on recommendations of NRC to meet the realrequirements of the commercial poultry farms.

Reduced prevalence of diarrhea and mortality has been reported after dietary supplementation with zinc compounds in swine with naturally acquired colibacillosis and those challenge-exposed with Serpulina hyodysenteriae; however, the usefulness of this approach for control of enteric diseases of swine remains to be determined. To examine the effect of dietary zinc-containing compounds on the colonization and development of cecal lesions associated with S hyodysenteriae infection, a defined diet alone or with added ZnO, ZnSO4, or Zn-methionine complex to a final concentration of approximately 6,000 mg of Zn2+/kg of complete feed was fed ad libitum to 156 female mice (strain C3H/HeN) for 10 days prior to oral inoculation either with S hyodysenteriae or sterile trypticase soy broth. Rations were continued for 42 days, while at weekly intervals, 3 mice/group were necropsied for determination of body weight, cecal weight, liver zinc concentration, presence of S hyodysenteriae in the cecum, and gross and histologic assessments of cecal lesions. From postinoculation day 0 to 42, the liver zinc concentration of mice fed the zinc-supplemented diets was approximately twice that of mice fed the basal diet, irrespective of the source of zinc. From postinoculation day 7 through 42, the overall recovery rate of S hyodysenteriae in infected mice fed the basal diet was 77.8%. In contrast, recovery rates of S hyodysenteriae from S hyodysenteriae-inoculated mice fed the zinc-supplemented diets were 0% for Zn-methionine and ZnO and 16.7% for ZnSO4. Mice fed the basal diet had significantly (P < 0.05) higher weight gain than mice fed the zinc-supplemented diets. However, the severity of cecal lesions, as determined by histologic examination and quantitative determination of longitudinal crypt length of the cecum was significantly (P < 0.05) less in mice fed the zinc-supplemented diets than in mice fed the basal diet. Data from this study indicate that dietary supplementation with 6,000 mg of zinc/kg of feed significantly reduced the recovery rate of S hyodysenteriae and provided partial protection against development of cecal lesions in mice inoculated with S hyodysenteriae. However, at this concentration, zinc had a deleterious effect on growth of the mice.

Adhesion of equine spermatozoa to homologous oviduct epithelial cells (OEC) in vitro results in specific changes in spermatozoa and OEC function. To test the hypothesis that adhesion of spermatozoa affects protein synthesis and secretion by OEC, the following treatment groups were established in culture: OEC with culture medium only; control spermatozoa in culture medium only; OEC in coculture with spermatozoa; and OEC and spermatozoa in coculture, but physically separated by a microporous membrane. The experiment was replicated within each of 4 ejaculates from 3 stallions. De novo protein secretion by OEC was measured and compared by incorporation of [35S]methionine, and evaluated, using two-dimensional polyacrylamide gel electrophoresis and fluorography. Monolayers of OEC secreted a large number of proteins of molecular mass ranging from 14 to 205 kd. Adhesion of spermatozoa consistently caused reduced synthesis of 2 OEC secretory proteins and new or increased synthesis of 6 proteins. When spermatozoa and OEC were separated by a microporous membrane, some but not all of these changes were duplicated. Synthesis of 3 OEC secretory proteins, unaffected by binding of spermatozoa, was reduced when spermatozoa were prevented from contact with OEC by a microporous membrane. Adhesion of equine spermatozoa to homologous OEC monolayers and presence of equine spermatozoa resulted in qualitative and quantitative changes in synthesis and secretion of proteins by OEC. These changes have implications for storage, longevity, and maturation of spermatozoa.

Eimeria mitis, 2 strains, chickens, reduced intestinal absorption of glucose and L-methionine, reduced weight gain, depigmentation of plasma, gross lesions absent

Objective: The current study investigated the effects of supplying ruminally protected amino acids (AA) (lysine, L; and methionine, M) and dietary protein levels on the performance of late-nursing ewes. Materials and Methods: Thirty-one Awassi ewes nursing single lambs were individually housed and assigned randomly to one of four treatment groups (2 × 2 factorial design). Ewes in treatment groups were (with supplemental RPL and RPM) or were not (without supplemental RPL and RPM) supplemented with lysine (8.5 gm/day) and methionine (4 gm/day) and were fed diets containing either 13.2 (moderate protein) or 11.1% (low protein) protein. Results: No interactions between supplemental AA and dietary protein levels were observed. Supplying ewes with L and M did not affect (p &ge; 0.06) their nutrient intake or their final body weights (BWs). Additionally, milk composition, yield, and efficiency were not affected by supple¬mental L and M. Decreasing dietary protein levels did not affect (p = 0.13) the final BWs, milk yield, composition, and efficiency but decreased (p &lt; 0.01) nutrient intake of ewes. Conclusion: Under our study conditions, reducing the protein contents of the diets from 13.2% to 11.1% had no negative impact on late-nursing ewes. Regardless of dietary protein level, the beneficial effect of supplying L and M was not evident. [J Adv Vet Anim Res 2024; 11(3.000): 711-716]

Objective: This study was conducted to produce and evaluate protected amino acids (AAs) against degradation in the rumen with greater bioavalibility and without the problems associated with polymer coating and the effect this has on calf performance. Materials and Methods: In the first step, essential AAs methionine and lysine were reacted with two chemical compounds (Benzaldehyde and Glutaraldehyde) in an attempt to make ligands for producing protected AAs. The physico-chemical characterization, melting point, and mass spec¬trometric of products were estimated. These products were fed to 36 Holstein dairy calves with 110 ± 0.50 kg of average body weight and an age of 110 ± 10 days. Calves were randomly assigned to six treatments. This study was done with six treatments as a completely randomized one-way design. Results: Feed consumption and average daily gain were less for control animals and those fed methionine and lysine glutaraldehyde compared to other treatments. The largest chewing time was observed for methionine and lysine glutaraldehyde, respectively, and the least was control. There was no difference for energy consumption, dry matter intake, or blood metabolites among the six treatments. The greatest total protein content was related to methionine and lysine glutaraldehyde treatment and the least total protein was observed in control treatment. Conclusion: It can be concluded that the use of chemical methods to protect AAs can be applied and may have some beneficial effects. [J Adv Vet Anim Res 2020; 7(2.000): 229-233]