Accumulation of 2,8 dihydroxyadenine in bovine liver, kidneys, and lymph nodes

A variety of tissues from 20 cattle slaughtered at federally inspected facilities contained abundant light green to greenish-yellow material. Gross lesions were most common in the liver and hepatic lymph nodes. Less frequent lesions were present in the mediastinal, renal, intercostal, and gastric lymph nodes. The material was most prominent in the portal triads, and in the medullary sinuses of the lymph nodes, at times occupying up to one half of the nodal mass. Renal calculi were present in one animal. Histologically, the condition was characterized by the intracytoplasmic accumulation of innumerable brown, acicular crystals in hepatocytes, macrophages, and renal tubular epithelial cells. Less frequent large aggregates of extracellular crystals were found in the lumens of renal tubules and in portal triads. Crystals were highly birefringent when examined using polarized light. The crystals were identified as 2,8 dihydroxyadenine using X-ray diffraction, electron diffraction, infrared spectroscopy, and mass spectrometry. In mammals, adenine is normally converted to adenylate by the enzyme adenine phosphoribosyltransferase. When adenine phosphoribosyltransferase is absent, deficient, or inhibited, adenine is oxidized to 2,8 dihydroxyadenine, which is extremely insoluble at physiological pH. In human beings, an autosomal recessive disease known as 2,8 dihydroxyadeninuria is caused by a deficiency of adenine phosphoribosyltransferase.     

Risk factors associated with the presence of Sarcocystis neurona sporocysts in opossums (Didelphis virginiana).

Sarcocystis neurona is the most important cause of equine protozoal myeloencephalitis (EPM) in horse in the Americas. The only known definitive host for this parasite in the United States is the opossum (Didelphis virginiana); however, despite the importance of the disease, the epidemiology of the parasite in the definitive host is poorly understood. To begin addressing these data gaps, potential risk factors were evaluated for their association with the presence of sporocysts of S. neurona in opossums live-trapped in March 1999 and November 1999 to May 2000. Sporocysts of S. neurona were found in 19 of the 72 animals examined. Potential risk factors evaluated were locality, trap date, age, gender, the presence of young in the pouch of females, and body condition score. Variables that were associated with the presence of S. neurona sporocysts were used in logistic regression analysis. Of the factors examined, season and body condition score were associated with increased odds of an animal harboring sporocysts.     

Determination of conjugated linoleic acid (CLA) concentrations in milk chocolate

The fatty acids from a series of milk-chocolate-based confectionery samples were analyzed as methyl esters by GC to determine the presence and amount of conjugated linoleic acid (CLA). A single peak corresponding to the 9-cis,11-trans isomer and ranging from less than 0.1% to nearly 0.2% of the total fatty acids, corresponding to up to 0.3 mg per g of chocolate, was observed. One of the chocolate extracts and a milk extract were subjected to silver ion HPLC and GC-MS in order to confirm the identity of the major isomer and tentatively identity minor isomers.     

Alfalfa cultivar response to phosphorus and potassium deficiency: Elemental composition of the herbage

While phosphorus (P) and potassium (K) use efficiencies in alfalfa (Medicago sativa L.) are subject to genetic control, selection for these traits also affects the utilization of other nutrients. It is not clear whether other nutrients are as susceptible to genetic alterations directly or whether alteration of P and K uptake may simply alter the general synergisms and antagonisms among the elements in plants.

Our objectives were to compare the P‐ and K‐use efficiencies of five commercial alfalfa cultivars (CVs) growing on a low‐P, low‐K calcareous soil, and to evaluate the impact of P and K fertilization on the herbage concentrations of these and other elements. The CVs were selected for uniformity of disease resistance and other agronomic traits. Three levels each of P and K fertilizer were applied in factorial combination, with CV as the whole plot and fertilizer treatment as the split plot. Herbage samples, consisting of the top half of the shoot, were collected at the first cut in 1992 and 1993 and were analyzed by wet digestion and inductively coupled plasma emission spectrometry (ICP).

There were appreciable amounts of aluminium (Al), iron (Fe), sulfur (S), and silicon (Si) in the alfalfa herbage but CV and soil treatment did not affect the concentrations of these elements. Plant breeding and selection for P‐use efficiency seems to be feasible. There was a positive soil P influence on herbage concentrations of sodium (Na), calcium (Ca), magnesium (Mg), and strontium (Sr) which was attributed to increased plant ATP. There was a negative effect of soil P on herbage K apparently due to the mutual antagonisms among K, Na, Ca, and Mg. There was significant variance among CVs for manganese (Mn) and zinc (Zn) but not for boron (B) and copper (Cu). Soil P had a negative effect on concentrations of B, Cu, Mn, and Zn in the herbage. Soil K had a negative effect on herbage B, Cu, and Mn. Only Cu approached deficiency levels, which needs further evaluation for this calcareous soil.     

Alfalfa cultivar responses to phosphorus and potassium deficiency: Biomass

Soil phosphorus (P) fertility needs for alfalfa (Medicago sativa L.) in the intermountain western United States have been a concern since the inception of irrigation during the late 19th century. Soil potassium (K) fertility needs have received much less attention because K deficiencies, related to long term use of high quality, low‐K irrigation water, have developed only in recent years. The objectives of this research were to compare the responses of five commercial alfalfa cultivars (CVs) to phosphorus (P) and K deficiency and to examine the interactions between CVs and P and K soil fertility. An experiment was established on a highly calcareous Redfield silt loam soil (Fine‐silty carbonatic, mesic Xeric Torrifluvents) that was low in both P and K. The CVs, planted in 1988, were studied through 1993. A 3x3 complete factorial combination of P and K fertilizer rates was established in a split plot design where CV was the whole plot. There was a significant CV x year interaction in biomass production that was not related to diseases or insects. There was also a significant CV x P interaction within and among years. Response to K fertility, though significant, was not prominent in this trial. Alfalfa CV performance trials should segregate CVs best adapted to short term (2–3 year) rotations from those best adapted to long term (4–5 year) rotations. Fertilizer effects on low‐K calcareous soils are short lived; moderate rates of K fertilizer should be applied each spring. Soil P requirements of alfalfa can be met by applying small rates annually or by applying enough for a 4‐ to 5‐year rotation. Phosphorus‐use efficiency by alfalfa may be improved by plant breeding and selection for this trait.     

Elevated CO2 does not exacerbate nutritional stress in larvae of a Pacific flatfish

Multiple aspects of climate change are expected to co‐occur such that ocean acidification will take place in conjunction with warming and a range of trophic changes. Previous studies have demonstrated that nutritional condition plays a significant role in the responses of invertebrates to ocean acidification, but similar studies have yet to be conducted with marine fishes. In this study, we examined the potential interactive effects of elevated CO₂ levels and nutritional stress on the growth and development of northern rock sole (Lepidopsetta polyxystra). Separate experiments examined the effects of these two environmental stressors during the pre‐flexion (3–31 days) and post‐flexion (31–87 days) larval stages. In both stages, the larval feeding regime has a much larger impact on growth rates than did the CO₂ level, and there was no observed interaction between stressors. By 31 days post‐hatch, larvae in the high‐feeding treatment were 84.2% heavier than the fish in the low‐feeding treatments, but there was no significant effect of CO₂ level on body size or condition. While overall growth rates were faster during the pre‐flexion stage, the effects of food limitation were greater for post‐flexion larvae undergoing metamorphosis, with the high‐feeding treatment fish being 3.3 times as heavy as fish in the low‐feeding treatments. These results have important implications for understanding the impacts of the multi‐faceted nature of climate change on population productivity of commercial fish species in the North Pacific.     

Effects of sow-crate design on health and performance of sows and piglets

The effects of sow-crate design on certain health and performance traits of 211 sows and their piglets were evaluated with a 2 X 2 X 4 factorial arrangement of crate width (narrow [N = 55 cm] or wide [W = 64] between lowest horizontal pipes), length (short [S = 183 cm] or long [L = 198] from rump stop to front gate) and side type (lower side of sow crate "fingered" [F], "bowed" bottom bar--marking the sow zone 19.3 cm wider at the bottom--20 cm above the floor [B], or straight bottom bar 20 cm [S20] or 25 cm above the floor [S25]). Between d 107 to 110 postcoitum and d 21 postpartum, no crate design variable affected the sow's body-weight change, but side type tended to affect the most prominent head-neck and leg integumentary lesions. Number of stillborn piglets/litter was greater with W crates than with N, except with crates having S20 sides, and was greater with L crates than with S. More piglets were crushed to death in W crates than N crates, and stillbirth frequency was greater in L crates than in S, but overall preweaning piglet mortality was affected by no crate-design feature. At both 7 and 21 d of age, piglets' knee lesions were most severe with S20 crates and least with S25, whereas face-lesion score was unaffected by crate design. Piglet body weight at age 21 d was least with S20 crates and greatest with F and S25. No crate-design variable affected within-litter variation in piglet growth rate. Sow-crate design affected important health and performance traits of piglets through postnatal d 21.