Changes in the ultrastructure of cardiac muscle in steers deprived of copper.

Young Friesian steers were fed for nine months on copper supplemented or depleted diets. Immediately after they had been killed, tissues were taken from the myocardium for examination by electron microscopy. Copper deficiency was associated with extensive changes in myofibrillar and mitochondrial morphology and distribution. It is suggested that the ultra-structural changes in the myocardium were specifically attributable to copper deficiency, the most likely underlying biochemical defect being lost of cytochrome oxidase activity.     

Evaluation of Heterotrophic Algae Meal as a Diet Ingredient for Channel Catfish,Ictalurus punctatus

Most microalgae evaluated in aquaculture diets have been produced autotrophically. In order to produce a cost‐efficient biomass at greater magnitudes for biofuel feedstock, heterotrophic production may be warranted. However, the chemical/nutritional attributes of these microalgae could differ from those grown autotrophically. An 8‐wk feeding trial was conducted to evaluate Chlorella spp. algae meal (AM) that had been cultured heterotrophically. The oil (lipid) was extracted to simulate biofuel production. Juvenile channel catfish, Ictalurus punctatus (5.7 ± 1.4 g; 8.9 ± 0.8 cm), were stocked at 10 fish/tank into fifteen 37.7‐L aquaria in a closed recirculating system and fed one of the five experimental diets to apparent satiation twice daily. Diets contained either 0 (control, CTL), 10, 20, or 40% AM and an additional diet containing 40% AM was supplemented with 2% lysine (40% AM+LYS). After 8 wk, there were no statistically significant differences in terms of survival, dressout percentages, whole‐body proximate composition, or fatty acid composition of the fillets among fish fed the diets containing varying levels of AM without added lysine. Feed consumption and weight gain for fish fed the 10, 40, and 40% AM+LYS diets were significantly greater than those fed the CTL diet. Feed conversion ratio was significantly lower for fish fed the 40% AM+LYS diet compared to those fed all other diets, which did not differ significantly from each other. These data indicate that channel catfish readily accept and can efficiently utilize heterotrophically produced AM at levels up to at least 40% of the total diet and that AM may enhance diet palatability.     

Effects of iron injection timing on suckling and subsequent nursery and growing-finishing performance and hematological criteria

Two experiments were conducted to evaluate the effects of Fe injection timing after birth on suckling and subsequent nursery and growing-finishing pig performance. The injectable Fe source used in both experiments was GleptoForte (Ceva Animal Health, LLC., Lenexa, KS). GleptoForte contains gleptoferron which is a Fe macromolecule complex. In Exp. 1, a total of 324 newborn pigs (DNA 241 × 600, initially 1.6 ± 0.04 kg body weight [BW]) within 27 litters were used. Two days after birth, all piglets were weighed, and six barrows and six gilts per litter were allotted to 1 of 6 treatments consisting of no Fe injection or 200 mg of injectable Fe provided in a single injection on d 2, 4, 6, 8, or 10 of age. Pigs were weaned (~21 d of age) and allotted to nursery pens with all pigs in each pen having received the same Fe treatment. In Exp. 2, a total of 1,892 newborn pigs (PIC 359 × C40; initially 1.5 ± 0.02 kg BW) within 172 litters were used. One day after birth, piglets were weighed, and 11 pigs within each litter were allotted to 1 of 6 treatments consisting of no Fe injection or 200 mg of injectable Fe provided on d 1, 3, 5, or 7 of age, or 200 mg on d 1 plus 200 mg on d 12 of age. Pigs were weaned (19 d of age) and placed in a commercial wean-to-finish facility in a total of 15 pens with equal representation of treatments in each pen. In both experiments, not providing an Fe injection after birth decreased (P < 0.05) preweaning average daily gain (ADG), weaning weight, and hemoglobin and hematocrit values compared with all other treatments. In Exp. 1, increasing the age that piglets received an Fe injection until 4 or 6 d after birth provided marginal evidence for an improvement (quadratic; P = 0.070) in preweaning ADG. For the nursery period, increasing the age that piglets received an Fe injection improved (quadratic; P = 0.013) d 80 BW, but there was no evidence of a difference (P > 0.10) in d 173 BW at the end of the grow-finish period. In Exp. 2, increasing the age that piglets received a 200 mg Fe injection showed no evidence of difference (P > 0.10) for subsequent nursery and growing-finishing ADG. In both experiments, hemoglobin and hematocrit values were decreased (linear; P < 0.05) at weaning with increasing age when pigs received an Fe injection. These experiments suggest that providing a 200 mg Fe injection within 7 d after farrowing is sufficient for optimizing preweaning and subsequent growth performance.     

Diel differences in blue whale (Balaenoptera musculus) dive behavior increase nighttime risk of ship strikes in northern Chilean Patagonia

The northern Chilean Patagonia region is a key feeding ground and a nursing habitat in the southern hemisphere for blue whales (Balaenoptera musculus). From 2014 to 2019, during 6 separate research cruises, the dive behavior of 28 individual blue whales was investigated using bio-logging tags (DTAGs), generating ≈190 h of data. Whales dove to significantly greater depths during the day compared to nighttime (day: 32.6 ± 18.7 m; night: 6.2 ± 2.7 m; P < 0.01). During the night, most time was spent close to the surface (86% ± 9.4%; P < 0.01) and at depths of less than 12 m. From 2016 to 2019, active acoustics (scientific echosounders) were used to record prey (euphausiids) density and distribution simultaneously with whale diving data. Tagged whales appeared to perform dives relative to the vertical migration of prey during the day. The association between diurnal prey migration and shallow nighttime dive behavior suggests that blue whales are at increased risk of ship collisions during periods of darkness since the estimated maximum ship draft of vessels operating in the region is also ≈12 m. In recent decades, northern Chilean Patagonia has seen a large increase in marine traffic due to a boom in salmon aquaculture and the passenger ship industry. Vessel strike risks for large whales are likely underestimated in this region. Results reported in this study may be valuable for policy and mitigation decisions regarding conservation of the endangered blue whale.     

Risk factors influencing death prior to discharge in 302 dogs undergoing unilateral adrenalectomy for treatment of primary adrenal gland tumours

Adrenalectomies for canine adrenal tumours are associated with peri-operative morbidity and mortality. Objectives of this study included assessing the prognostic value of tumour- or surgery-related variables in predicting peri-operative mortality and overall survival in dogs undergoing adrenalectomies for primary adrenal tumours as well as pre-treatment with phenoxybenzamine on survival to discharge with pheochromocytomas specifically. A multi-institutional retrospective cohort study was performed across nine institutions. Electronic medical record searches identified 302 dogs which met the inclusion criteria. Data collected included dog-related, tumour-related, treatment-related, surgery-related, and outcome variables. Univariate and multivariable logistic regression and cox proportional hazards models were used to identify variables associated with death prior to discharge and tumour-related survival. Overall, 87% of dogs survived to discharge with a tumour-related survival time of 3.96 years. Post-operative complications were reported in 25%. Increased surgical time (p = 0.002) and pre-surgical medical treatment other than phenoxybenzamine (p = 0.024) were significantly associated with increased peri-operative mortality while ureteronephrectomy (p = 0.021), post-operative pancreatitis (p = 0.025), and post-operative aspiration pneumonia (p < 0.001) were significantly associated with decreased overall survival. Phenoxybenzamine pretreatment had no effect on peri-operative mortality. Thirty-seven of 45 (82%) dogs with pheochromocytomas not pretreated survived to discharge, and 50 of 59 (85%) dogs with pheochromocytomas pretreated with phenoxybenzamine survived to discharge (p = 0.730). This study provides information on risk factors for death prior to discharge and tumour-related survival that may help guide clinical management and owner expectations. In addition, the study findings challenge the previously reported benefit of phenoxybenzamine for pretreatment of dogs undergoing adrenalectomies for pheochromocytomas.     

Performance of Pacific White Shrimp,Litopenaeus vannamei,Reared in Zero‐Exchange Tank Systems Exposed to Different Light Sources and Intensities

The development of biofloc production technology has generated significant commercial and research interest directed toward the inland culture of Pacific white shrimp, Litopenaeus vannamei. Most work to date has been conducted in greenhouses, where photoautotrophic organisms are significant contributors to system functionality. In more temperate locations, operations in insulated buildings would reduce heating costs. This experiment was designed to evaluate the effect of light on shrimp cultured in intensive biofloc systems. A 92‐d experiment was conducted in 3.8‐m³ tanks. There were five light treatments: (1) natural sunlight (SUN) as a control (midday: 718 lx); (2) one metal halide light (MHL) (1074 lx); (3) one fluorescent light (1FL) (214 lx); (4) two fluorescent lights (2FL) (428 lx); and (5) three fluorescent lights (3FL) (642 lx). Artificial light treatments operated on a 12:12 daily cycle. There were three replicate tanks per treatment and each was separated by black plastic to prevent light transmission between replicates. Each tank was stocked at 465 shrimp/m² of tank bottom (initial mean weight = 0.4 g). Light treatment had a significant (P≤ 0.05) impact on average individual weight, survival, harvest yield (kg/m²), and feed conversion ratio (FCR). Harvest yield and survival among shrimp in the SUN, MHL, and 1FL treatments were not significantly different. However, there was an inverse linear relationship (P≤ 0.05; R² = 0.76) between the number of fluorescent fixtures and survival, which was related to greater concentrations of filamentous bacteria as the intensity of fluorescent light increased, causing gill fouling. Natural light and MHL did not result in high concentrations of filamentous bacteria. These results indicate that natural light, metal halide lighting, and/or relatively low levels of fluorescent lighting are suitable for indoor production of Pacific white shrimp in biofloc systems. Light spectrum and intensity can affect bacterial community structure, which has a profound effect on shrimp survival and production.