Optimization of embryonic thermal programming confirms increased liver fattening in mule ducks and changes in lipid metabolism.

Introduction: The embryonic thermal programming (TM) in birds has been shown to impact several physiological parameters such as resistance to thermal stress, muscle growth or immunity. In mule ducks, it has recently been shown that TM can induce metabolic programming resulting in increased liver weight and fat storage after overfeeding. However, a decrease in hatchability and foie gras quality was also observed, suggesting that this technique needs to be optimized. Here, we tested a new thermal manipulation condition determined with the objective of avoiding negative impacts while maintaining or improving liver properties. Methods: The eggs of the control group were incubated at 37.6°C during the whole incubation period while those of the experimental group (TM group) were incubated at 39.3°C 16 h/24 h from the 11th day of incubation to the 21st. After hatching, all the animals were fed and raised under the same conditions until the age of 12 weeks. At this stage, one part of the animals was overfed and then slaughtered 2 h (to measure rapid changes in metabolism) or 10 h after the last meal (to obtain the best technological yields), while the other part was ration-fed and slaughtered 2 h after the last meal, at the same age. Results: An 8% increase in foie gras production was measured in the TM group compared to the control group without altering the quality of the final product (nor hatchability), confirming the successful optimization of the metabolic programming. Interestingly, these results allowed us not to reject the previously suggested hypothesis of a potential delay in metabolic processes involved in liver fattening in programmed animals, in particular by measuring a trend reversal regarding the amount of total hepatic lipids in both groups at 2 h and then 10 h after the last meal. Discussion: This study therefore validates the optimization of metabolic programming by embryonic thermal manipulation for duck liver fattening. The understanding of the mechanisms of embryonic thermal programming in birds remains today very incomplete and the search for epigenetic marks (main hypothesis of the concept of programming) at the origin of the observed phenotypes could be the next step of this work.

Identification of different critical embryonic periods to modify egg incubation temperature in mule ducks.

Egg incubation of mule ducks, mainly used for fatty liver production, is one of the critical phases in this sector. Based on hatching rate, the best incubation parameters have already been well described for poultry, but the literature on ducks is lacking. In this study, we tested different incubation conditions by varying two important factors, temperature and relative humidity, in mule ducks. These variations were applied at different periods during embryogenesis in order to measure the impact of environmental disturbances on different zootechnical performances. The temperature was increased by 1.5 °C (16 h/24) and the relative humidity was set up to 65%, during 10 days. Six 10-day developmental windows were tested, from embryonic day 9 to embryonic day 14. Our results are in line with previous reports showing that increasing incubation temperature, even when relative humidity is adjusted, can have a negative impact on duck embryonic mortality up to 24.5% for the condition E10-E20 (P < 10-5). However, the hatchability can be maintained at the level of the control groups when these modifications are applied on the latest windows (from the 11th embryonic day). Sex ratio, hatching BW, and internal temperature are also sensitive to these incubation changes, and their modification could have a major impact on later zootechnical performance. These results should contribute to the development or embryonic temperature programming approaches, especially for the fatty liver production industry.

Pilot study to quantify the time to clear dexamethasone from plasma and urine of adult horses following a single nebulisation.

OBJECTIVE: To quantify the time to clear dexamethasone from plasma and urine of horses following a single nebulisation. DESIGN: Experimental using six Standardbred mares. METHODS: Dexamethasone sodium phosphate (0.04 mg/kg) diluted in 0.9% sodium chloride was administered as an aerosol using a Flexineb E2® nebuliser. Blood samples (0, 2, 4, 6, 8, 10, 12, 24, 32, 48, 72 and 96 h) and urine samples (0, 1, 4, 8, 24, 32, 48, 72 and 96 h) were collected for analysis using liquid chromatography mass spectrometry. RESULTS: Maximum plasma concentrations (tmax ) were reached by the earliest detection point (2 h) after nebulisation (0.6-1.8 ng/mL), but was no longer detectable at 48 h. However, in one horse 0.1 ng/mL was found at 96 h after three consecutive readings of 0 ng/mL. The tmax in urine was reached by the earliest collection point (1 h) after nebulisation (3.2-23.8 ng/mL), but was no longer present in urine at 72 h in five horses, while detectable levels (0.1 ng/mL) were still present at 96 h in one horse. CONCLUSIONS: A single dose of 0.04 mg/kg of DSP administered as an aerosol through a FlexinebE2® mask was no longer detectable in blood at 48 h in six horses tested, but one horse returned a reading of 0.1 ng/mL at 96 h after having no detectable levels. Dexamethasone was not detectable in urine at 72 h in five horses but was detectable at a low concentration (0.1 ng/mL) at 96 h in one horse.

End-to-side anastomosis of the left ventral colon to the small colon in a neonatal foal with segmental agenesis of the large colon.

CASE REPORT: A newborn foal was referred for evaluation because it had not passed meconium, despite the administration of four enemas. Abdominal radiographs and ultrasound scans showed generalised gaseous distension of the intestine and there was no observable meconium in the colon. Positive contrast colography showed contrast medium extending to the transverse colon. An exploratory laparotomy confirmed the absence of the left and right dorsal colon and the pelvic and diaphragmatic flexures. An end-to-side anastomosis of the left ventral colon to the midpoint of the small colon was performed. The foal recovered from anaesthesia and surgery uneventfully and immediately began suckling from the mare, with no signs of abdominal pain in the postoperative period. The foal began to pass soft faeces 3 days after surgery and at 6 months after surgery the foal was clinically normal and growing at a similar rate to its cohort. CONCLUSION: Intestinal atresia is a rare condition in foals, but should be considered as a differential diagnosis in foals that fail to pass meconium. Early recognition and surgical intervention can offer an improved chance of short-term survival in cases where there is adequate intestine to anastomose. An end-to-side anastomosis technique can be used where an end-to-end technique is not practical because of the difference in diameter of the proximal and distal intestinal segments.