Incorporation of [3H]proline into collagen and other proteins in rats fed diets with various zinc concentrations

Correlations of capture, transport, and nutrition with spinal deformities in sandtiger sharks, Carcharias taurus, in public aquaria

A number of captive sandtiger sharks (Carcharias taurus) in public aquaria have developed spinal deformities over the past decade, ranging in severity from mild curvature to spinal fracture and severe subluxation. To determine the frequency and etiologic basis of this disease, U.S. public aquaria participated in a two-stage epidemiologic study of resident sharks: 1) a history and husbandry survey and 2) hematology, clinical chemistry, and radiography conducted during health exams. Eighteen aquaria submitted data, samples, or both from 73 specimens, including 19 affected sharks (26%). Sharks caught off the Rhode Island coast or by pound net were smaller at capture and demonstrated a higher prevalence of deformity than did larger sharks caught from other areas via hook and line. Relative to healthy sharks, affected sharks were deficient in zinc, potassium, and vitamins C and E. Capture and transport results lead to two likely etiologic hypotheses: 1) that the pound-net capture process induces spinal trauma that becomes exacerbated over time in aquarium environments or 2) that small (and presumably young) sharks caught by pound net are exposed to disease-promoting conditions (including diet or habitat deficiencies) in aquaria during the critical growth phase of their life history. The last hypothesis is further supported by nutrient deficiencies among affected sharks documented in this study; potassium, zinc, and vitamin C play critical roles in proper cartilage-collagen development and maintenance. These correlative findings indicate that public aquaria give careful consideration to choice of collection methods and size at capture and supplement diets to provide nutrients required for proper development and maintenance of cartilaginous tissue.

Zinc in wound healing: theoretical, experimental, and clinical aspects

Zinc is an essential trace element in the human body and its importance in health and disease is appreciated. It serves as a cofactor in numerous transcription factors and enzyme systems including zinc-dependent matrix metalloproteinases that augment autodebridement and keratinocyte migration during wound repair. Zinc confers resistance to epithelial apoptosis through cytoprotection against reactive oxygen species and bacterial toxins possibly through antioxidant activity of the cysteine-rich metallothioneins. Zinc deficiency of hereditary or dietary cause can lead to pathological changes and delayed wound healing. Oral zinc supplementation may be beneficial in treating zinc-deficient leg ulcer patients, but its therapeutic place in surgical patients needs further clarification. Topical administration of zinc appears to be superior to oral therapy due to its action in reducing superinfections and necrotic material via enhanced local defense systems and collagenolytic activity, and the sustained release of zinc ions that stimulates epithelialization of wounds in normozincemic individuals. Zinc oxide in paste bandages (Unna boot) protects and soothes inflamed peri-ulcer skin. Zinc is transported through the skin from these formulations, although the systemic effects seem insignificant. We present here the first comprehensive account of zinc in wound management in relation to current concepts of wound bed preparation and the wound-healing cascade. This review article suggests that topical zinc therapy is underappreciated even though clinical evidence emphasizes its importance in autodebridement, anti-infective action, and promotion of epithelialization.

Organ and tissue weight presentation in rat populations

Multiple ways of reporting organ weights are sources of confusion in literature. This study was designed to determine if there is a linear relationship between body weights and selected organ and tissue weights in groups of rats after different liquid feeding options. A randomized 2 x 2 x 2 factorial, randomized block design was used with 40 postpubescent male rats with two levels of feeding schedules, kilocalorie levels, and fiber contents. In addition to a skeletal muscle, 13 abdominal and thoracic organs or tissues were weighed. Pearson product-moment correlation coefficients and regression analyses were completed to determine the relationship between these weights and the final body weights. Findings support the need to use different approaches in order to accurately report various organ and tissue weights.

The effects of halofuginone and salinomycin, alone and in combination, on live performance and skin characteristics of female broilers: influence of a high-proline diet supplemented with ascorbic acid and zinc

Live performance and carcass quality of female broilers were evaluated under four coccidiostat programs (CP) and two feed treatments. The CP consisted of halofuginone (H) and salinomycin (S), fed either continuously (HH and SS) or in rotational programs (HS and SH), during the starter (1 to 21 d) and grower (22 to 35 d) periods, respectively. All groups received an unmedicated withdrawal feed from 36 to 42 d. Feed treatments consisted of a control and a fortified diet high in proline and supplemented with additional ascorbic acid and zinc (50 birds per pen; 4 pens per feed; 8 pens per CP). In addition to live performance and skin puncture strength, carcass quality attributes following processing (at 43 d of age) were assessed. No CP by feed interactions were detected for any of the variables measured. The CP treatments did not differ for live performance. Birds on fortified feed were heavier at 21 d (P < .001) and had an improved feed conversion at 42 d (P < .05). Skin puncture strength was significantly reduced for the birds fed H, either in continuous (HH) or rotational programs (HS and SH). Skin sores-scratches and tears were lowest for the SS and SH groups. The HH treatment resulted in fewer grade A carcasses (P < .001). Halofuginone, when fed continuously or in the starter feed, affected carcass quality of broilers. Higher dietary proline or supplementation with ascorbic acid and zinc did not appear to alleviate the effects of halofuginone on skin quality.