Experimental reproduction of malabsorption syndrome with different combinations of reovirus, Escherichia coli, and treated homogenates obtained from broilers

Attempts to reproduce malabsorption syndrome (MAS) by oral inoculation with several different combinations including intestinal homogenate, reovirus, and hemolytic Escherichia coli obtained from MAS-affected chickens and intestinal homogenate from healthy chickens (healthy homogenate) were performed in 1-day-old specific-pathogen-free (SPF) broilers. The MAS homogenate, serving as a positive control, induced weight gain depression and intestinal lesions such as cystic crypts of Lieberkuhn, villus atrophy, and lymphoid and/or granulocytic infiltration. The healthy homogenate, the formalin-treated MAS homogenate, the formalin-treated healthy homogenate, and phosphate-buffered saline caused neither weight gain depression nor intestinal lesions. We were able to reproduce both weight gain depression and intestinal lesions by inoculation of reovirus either combined with the formalin-treated MAS homogenate or combined with healthy homogenate. Surprisingly, when hemolytic E. coli was added to the combination of reovirus with formalin-treated MAS homogenate, this did not cause weight gain depression although this combination caused the described intestinal lesions. Identical results were obtained with the combination of formalin-treated MAS homogenate with hemolytic E coli or the combination of reovirus with hemolytic E. coli. The intestinal lesions were more severe and developed faster by combinations including reovirus and formalin-treated MAS homogenate. This study indicates that a combination of enteropathogenic reovirus with other agents or substances that are present in an intestinal homogenate from MAS-affected and healthy chickens can induce MAS in SPF broilers. Escherichia coli is not essential for induction of weight gain depression but can play a role in development of intestinal lesions. Furthermore, intestinal lesions alone will not always result in weight gain depression.     

Indices of renal function: reference values in normal horses

Urine and blood samples were taken at the same time from normal adult horses presented for routine investigations to establish reference values for a variety of parameters reported to be useful in the clinical evaluation of renal function. Blood biochemical values were consistent with previous studies and had well-defined normal ranges. Parameters representing urine concentration and electrolyte excretion however, varied widely reflecting the ability of the healthy kidney to change the composition of urine in response to differences in environment and management. Percent creatinine clearance ratios for potassium in particular were lower than those reported in normal horses in previous studies. Rational interpretation of these latter measurements should accept a wide range of normal values and management conditions must be considered in this interpretation.     

Insulin sensitivity decreases with obesity, and lean cats with low insulin sensitivity are at greatest risk of glucose intolerance with weight gain

This study quantifies the effects of marked weight gain on glucose and insulin metabolism in 16 cats which increased their weight by an average of 44.2% over 10 months. Significantly, the development of feline obesity was accompanied by a 52% decrease in tissue sensitivity to insulin and diminished glucose effectiveness. In addition, glucose intolerance and abnormal insulin response occurred in some cats. An important finding was that normal weight cats with low insulin sensitivity and glucose effectiveness were at increased risk of developing impaired glucose tolerance with obesity. High basal insulin concentrations or low acute insulin response to glucose also independently increased the risk for developing impaired glucose tolerance. Male cats gained more weight relative to females and this, combined with their tendency to lower insulin sensitivity and higher insulin concentrations, may explain why male cats are at greater risk for diabetes. Results suggest an underlying predisposition for glucose intolerance in some cats, which is exacerbated by obesity. These cats may be more at risk of progressing to overt type 2 diabetes mellitus.     

A Case of Successful Pregnancy in a Ewe with Uterus Didelphys

Uterus didelphys is a rare congenital abnormality of the reproductive tract. Although it occurs in various species, there are no published reports describing pregnancy outcome in association with this abnormality. Herein we describe a case of successful unilateral singleton pregnancy in a ewe incidentally found to have uterus didelphys during the course of a biomedical research study. The pregnancy was established using assisted reproductive techniques and interrupted in late gestation, at which point the abnormality was identified. Serial ultrasound assessment of foetal biometry revealed a normal foetal growth trajectory. Despite a 45% reduction in placentome number, total placentome weight was near normal secondary to compensatory placentome growth and development. To our knowledge, this is the first detailed report of normal foetal growth in an animal with uterus didelphys and illustrates the ability of the ovine placenta to adapt to a reduced number of placentomes and maintain foetal nutrient supply.     

Leukotrienes Affect Secretory Function of Ovarian Cells In Vitro*

The aim of this study was to determine which cells are the source of production and target for leukotriene (LTs) action within the bovine ovary. Luteal (CL, days 14–16 of the oestrous cycle), steroidogenic cells (LSC) and endothelial cells (LEC) of the bovine corpus luteum (CL), and granulosa cells (GC) were isolated enzymatically, cultured in a monolayer and incubated with LTC₄, LTB₄, Azelastine (an antagonist of LTC₄) or Dapsone (an antagonist of LTB₄). Then cells were collected for determination of mRNA expression for LT receptors (LTRs) and 5‐lipoxygenase (5‐LO) by real time RT‐PCR, and media were collected for determination of prostaglandin (PG)E₂, F_2α, progesterone (P4; LSC only), endothelin‐1 (ET‐1; LEC only) and 17‐β oestradiol (E2; GC only). The greatest mRNA expression for LTR‐II and 5‐LO were found in LEC, whereas LTR‐I mRNA expression did not differ among cell types. The level of PGE₂ increased after LTs treatment in each type of ovarian cell, excluding LTC₄ treatment in LEC. The secretion of PGF_2α was also increased by LTs, but decreased after LTB₄ treatment of LSC. In GC cultures, both LTs stimulated E2 secretion; in LEC cultures, LTB₄ stimulated whereas LTC₄ inhibited P4 secretion; in LEC cultures, LTC₄ stimulated but LTB₄ inhibited ET‐1 secretion. The results show that LTs are produced locally and are involved in PGs production/secretion in all examined cells (LSC, LEC and GC) of bovine ovary. Leukotriene treatment modulate secretion of E2, by GC, P4 by LSC and ET‐1 by LEC, which indicates that LTs are involved in regulation of ovarian secretory functions.     

Lactose Synthase Components in Milk: Concentrations of α-Lactalbumin and β1,4-Galactosyltransferase in Milk of Cows from Several Breeds at Various Stages of Lactation

It is believed that milk production is determined by the number and activity of mammary secretory cells. Secretory activity, as assessed by milk volume, depends on secretion of the major osmole in milk, lactose, which is produced by lactose synthase. The amount of either of the two proteins in lactose synthase may regulate milk production. The objective of this study was to determine whether the concentrations in milk of the two components of lactose synthase, α‐lactalbumin (α‐LA) and β1,4‐galactosyltransferase (B4GALT), were related to genetic background, stage of lactation, breed or parity of dairy cows. α‐Lactalbumin and B4GALT concentrations were measured by ELISA and by enzyme assays, respectively, from single milk samples. Two herds with a total of 279 cows were used in the analysis. One herd contained Ayrshire, Brown Swiss, Holstein and Jersey cows; the second herd contained two groups of cows; Holsteins selected for high milk production and Holsteins with 1960s genetics. The α‐LA concentration in milk was greater in Jerseys and Ayrshires than in Holsteins and Brown Swiss. However, no difference in α‐LA concentration was observed in milk from high and low genetic merit cows in the Minnesota herd or among different genetic backgrounds in the Illinois herd. β1,4‐Galactosyltransferase concentrations were similar for all groups that were analyzed. α‐Lactalbumin concentrations were positively correlated with milk protein concentration, milk fat concentration and lactose concentration. β1,4‐Galactosyltransferase concentration in milk exhibited a strong positive correlation with number of days in milk. Although the concentration of B4GALT increased as lactation progressed, the values did not show any correlation with persistency of lactation or late lactation milk production. In conclusion, this survey shows that the two components of lactose synthase are each correlated to protein concentration and individually correlated to the concentration of other milk components and stage of lactation.