The effect of tryptophan supplementation of diets of restricted- and unrestricted-fed young pigs

Young pigs (body weight 15-25 kg) were used to study the effect of graded levels of tryptophan supplementation to a diet containing 2.5 g tryptophan/kg dry matter (DM) and having a tryptophan to lysine ratio of 0.17 under restricted and unrestricted feeding conditions. Ad libitum feed intake and growth rate were 0.99 kg DM/day and 0.84 kg/day, respectively, and were not affected by supplementation of 0.2, 0.4, 0.6, 0.8 and 1.0 g tryptophan/kg diet. In restricted-fed piglets (80% of ad libitum intake) tryptophan supplementation did not improve growth rate. Therefore, greater optimum tryptophan to lysine ratios for young fast growing pigs, as concluded from results of some recently published studies in contrast to results of other studies, could not be confirmed. Possible reasons for discrepancies in published values for optimum tryptophan supply are briefly discussed. In accordance with general recommendations given in the literature, it can be concluded that a tryptophan to lysine ratio between 0.17 and 0.18 is sufficient to reach high feed intake and high growth rate in young pigs, when adequately supplied with lysine and other amino acids.     

Oral malignant melanoma – the effect of coarse fractionation radiotherapy alone or with adjuvant carboplatin therapy

A retrospective study was undertaken of dogs presented to the Animal Health Trust for treatment of oral malignant melanoma, without radiographic evidence of pulmonary metastases. Group 1 (n = 13) received radiotherapy of the primary and any lymph node metastases (4 weekly fractions of 9 Gy); and group 2 (n = 15) were treated the same but additionally received between two and six doses carboplatin at 300 mg m^?2 every 3 weeks. Median survival times for the two groups were 307 and 286 days, respectively (P > 0.05). In addition, carboplatin therapy did not significantly reduce the proportion of dogs dying due to metastases (three from group 1 and four from group 2). We found no evidence of a beneficial effect of carboplatin therapy over radiotherapy alone.     

Response to lysine in a wheat gluten diet in adult minipigs after short-and long-term dietary adaptation as assessed with an indicator amino acid oxidation and balance technique

An experiment was conducted to examine the response to wheat gluten (WG)-based diets at two lysine levels in adult minipigs (23 kg BW) using the indicator AA oxidation (IAAO) approach and N balance. Twenty minipigs (n = five per group), fitted with reentrant ileoileal cannulas allowing collection of ileal effluents, were fed restrictively two WG-based diets (WG and WG + Lys; 2.7 and 6.6 g of lysine/kg, respectively) for adaptation periods of 10 and 100 d. On d 7 and 9, for pigs fed the diets for 10 d, and on d 97 and 99, for pigs fed the diets for 100 d, primed i.v. fasted/fed tracer protocols with [(13)C]bicarbonate, and [(13)C]leucine were performed. With the WG diet, [(13)C]bicarbonate recoveries (%) were lower irrespective of the adaptation period, and higher during the fed period (fasted: WG + Lys = 82.5, and WG = 69.1; fed: WG + Lys = 90.6, and WG = 85.9; P < 0.05). Leucine oxidation rate was higher with the lower lysine intake (WG = 194.6 vs. 109.5 mg/[kg BW x d]; P < 0.05). Wheat gluten feeding resulted in a negative leucine balance independent of the adaptation period (WG = -29.1, and WG + Lys = 48.2 mg/[kg BW x d]; P < 0.05). In contrast with the IAAO method, N balance did not differ between the two lysine intakes, possibly because of an underestimation of N losses. The finding of a lower (13)C bicarbonate recovery with the lower dietary lysine intake suggests that caution should be taken in using a single recovery factor for all AA oxidation studies.     

Swine dysentery in a sow herd

Summary

An acute outbreak of swine dysentery (Doyle) on a farrowing farm is described. Besides clinical signs of enteritis a general loss of condition was seen throughout the herd. This resulted in a decreased fertility and breeding performance among sows and an increase in piglet mortality. Several dehydrated sows aborted.

The outbreak was stopped by oral treatment with lincomycin/spectinomycin 1:1. In the course of the treatment all animals and buildings were washed and disinfected. The use of pharmacotherapeutics in treating swine dysentery is discussed with emphasis on the involuntary induction of carriers.     

Relationship between latency of brainstem auditory‐evoked potentials and head size in dogs

Summary

Cranium and brainstem dimensions were measured in 32 postmortem dog heads. Positive correlations were found between cranium length (CL) and brainstem length (BL) (r=0.87), between cranium width (CW) and brainstem width (BW) (r=0.83), and between cranium distance (CD = CL CW/2) and brainstem distance (BD = BL+BW/2) (r=0.91). Positive correlation coefficients were also found between CL and CW (r=0.90), and between BL and BW (r=0.85). It was concluded that head size accurately reflected brainstem size. A least squares estimation of the brainstem distance (BD) from CL and CW values was BD = 10.9 + 0.16 (CL CW/2) (BD, CL and CW in mm).

Brainstem auditory evoked potentials (BAEPs) and cranium dimensions were measured in 43 dogs (86 ears) with different head size, body size, sex and age. Wave form, absolute and interpeak latencies and correlation coefficients, relating latencies to cranium dimensions and body weight, were analysed CL, CW, and CD were positively correlated with body weight (r=0.93, 0.70 and 0.93, respectively), and CL, CW, and CD were correlated with age (r=0.33, 0.52 and 0.40, respectively). BAEPs consisted of five distinct positive peaks (I to V). Secondary positive peaks following peaks I and II were seen in 60% (I') and 90% (II') of the recordings. Late waves were recorded in 90% (VI), 50% (VII), and 25% (VIII) of the recordings. Latencies increased with decreasing stimulus intensity level (from 90 dB to 10 dB hearing level, HL),especially for peaks I, II, V, and the I‐V interpeak interval Absolute and interpeak latencies were positively correlated with cranium distance and body weight. Correlation coefficients increased as wave latencies increased At 90 dB HL, the highest correlation coefficients, relating cranium distance to peak V and the I‐V interpeak latency, were 0.55 and 0.53 (P < 0.00001), respectively. Regression analysis showed that each 1 cm increase in cranium distance was accompanied by an increase of 0.006 ms in the latency of wave I, 0.03 ms for wave III, 0.05 ms for wave V, and 0.05 ms for the I‐V interpeak interval Regression analysis showed that an increase of 1 kg in body weight was accompanied by an increase of 0.001 ms in the latency of wave I, 0.005 ms for wave III, 0.011 ms for wave V, and 0.01 ms for the I‐V interpeak interval. It is concluded that head size, which accurately reflects brain size, is a relevant source (25%) of intersubject variance of BAEP latencies in the dog.     

Antigen quantification as in vitro alternative for potency testing of inactivated viral poultry vaccines

Abstract

Routine batch control of licensed inactivated viral vaccines for poultry usually includes a potency assay as a measure of vaccine efficacy. Potency assays often consist of vaccination‐challenge experiments in the target species or in laboratory animals. Instead of measuring the protection of vaccinated animals against virulent pathogens, the serological response after vaccination can be quantified for some vaccines. In vitro antigen quantification assays would be attractive alternatives for the current potency assays because the time and costs involved could be greatly reduced and animal use could be avoided. Such in vitro assays will only be acceptable when the correlation between results and efficacy or potency has been demonstrated convincingly.

The results of our studies on antigen quantification assays indicate that, in principle, quantification of viral antigens from inactivated oil‐adjuvanted vaccines is feasible and reproducible using specially developed antigen capture ELISAs in combination with specific software for statistical analysis of the ELISA data. We have developed methods to quantify the haemagglutination‐neuraminidase (HN) and fusion (F) proteins of Newcastle disease virus (NDV), the viral protein 3 (VP3) of the infectious bursal disease virus (IBDV), and the spike‐1 (S1) protein of the infectious bronchitis virus (IBV). Vaccination experiments with inactivated ND vaccines indicate that the in vitro quantified HN‐ or F‐proteins of NDV are reliable indicators of the serological response after vaccination.     

Organisms associated with the sandy-beach bivalve Donax serra Röding,with a description of Cercaria serrae sp. nov. (Trematoda)

Examination of two collections of Donax serra from a South African west coast beach revealed the presence of Ciliophora, Trematoda, Nematoda and a parasitic pycnogonid. This is the first record of a pycnogonid from the genus Donax and the first published report of such a parasite from any southern African bivalve mollusc. One of the two trematode species found is described as new and its epidemiology is discussed briefly. No epibiota were found on the bivalve shell.     

Yield and morphological responses of a forage sorghum to mefluidide

Abstract

Due to rapid growth, stem build‐up in forage sorghum crops often leads to considerable wastage by animals and consequent loss of production. In this study the potential of the chemical plant growth regulator, mefluidide, for modifying the morphology of forage sorghum was examined. Mefluidide was applied to two consecutive plantings of forage sorghum at 0; 0,14 and 0,28 kg/ha. Treatment with mefluidide suppressed stem elongation of sorghum plants and stimulated tillering 4–6 weeks after application. After 6 weeks the stem:leaf ratio of treated plants was significantly lower (P ≤0,05) than that of control plants. On average, total dry matter (DM) yield was marginally higher for the control, but DM yield of leaf material was significantly higher. (P ≤0,05) for treated plots from 6 weeks after mefluidide application. No significant differences were observed between levels of mefluidide but responses of different variables over time differed between plantings. This was associated with different stages of plant growth when mefluidide was applied and different environmental conditions for two plantings.     

Effect of Food Availability on the Physiological Responses to Water Deprivation in Ponies

Six ponies were deprived of drinking water and food and compared over 24 hours with nondeprived ponies, ponies deprived of water but with food available, and ponies deprived of food but with water available. When food was eaten during water deprivation, plasma osmolality rose 4% from 284 mOsm/kg to 295 mOsm/kg. During water and food deprivation, plasma osmolality failed to rise, even over 24 hours, and usually fell. Packed cell volume was higher when food but not water was available. Food and/or water deprivation had no significant effect on plasma protein concentration. When food was available, the ponies drank three times more water (13.1 ± 2.1 kg) than when water but not food was available (3.5 ± 1.4 kg). Blood volume changes were calculated from packed cell volume and plasma protein data, and it was found that blood volume did not change significantly with deprivation. Urine volume did not vary with deprivation, but free water clearance changed significantly, falling when food but not water was available. Under these conditions, blood volume is maintained, but the mechanisms are not clear. When deprived of both drinking water and food, ponies failed to develop the hyperosmolality expected under these conditions. Water deprivation while food is available is a more powerful challenge to water and electrolyte homeostasis than deprivation of both food and water.     

Laparoscopic Anatomy of the Abdomen and Laparoscopic Ligating Loops,Electrocoagulation, and a Novel Modified Electroligation Ovariectomy in Standing Mare

The purpose of this study was to provide a detailed laparoscopic anatomy of the caudal abdominal region of mare in a standing position and to evaluate and modify a technique for standing laparoscopic ovariectomy using combination between hand-tied ligating loop and electrocoagulation techniques, as the ligating loops, electrocoagulation, and modified electroligation laparoscopic ovariectomy were applied using nine adult mares. Laparoscopy was practical and effective for direct visual examination of internal abdominal organs in the mare. Ventral dislocation of abdominal viscera after pneumoperitoneum was established with the mare in standing position, which provided an excellent inspection of the dorsal and ventral structures in the peritoneal cavity on the right and left sides. Standing laparoscopic ovariectomy using an electroligation modified method was considered a safe and effective method for hemostasis of the mesovarium, technically easy, time saving, and economical. The mean surgical time for bilateral ovariectomy was 40 ± 7.63, 60 ± 5.25, and 85 ± 6.43 minutes for electroligation-modified technique, ligating loops technique, and electrocoagulation technique, respectively.