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Cement kiln dust (CKD), samples of which have been reported to stimulate growth in cattle and sheep, was fed to weanling pigs in a 42-d experiment. CKD at levels of 1.5 and 3.0% was added to a corn-soybean meal-oats-whey-type diet containing inadequate amounts of Ca (.4% of the diet) to provide final dietary Ca levels of .85 and 1.3%. A diet containing 3% limestone (1.3% dietary Ca) served as a positive control. Body weight gain was depressed by 3.0% CKD, and histopathological lesions of the humerus, not typical of nutritional secondary hyperparathyroidism or rickets, were observed. The lesions detected were osteonecrosis, thinning of the cortex and reduction in the width of the epiphyseal cartilage. Width of the proximal epiphyseal plate and cortical index of the humerus (width of cortex divided by total diameter at narrowest point of diaphysis) were smaller in pigs fed 3% CKD than in pigs fed 3% limestone. CKD contained 2.3% Al, 15 ppm Cd and 110 ppm Pb, providing 690, .45 and 3.3 ppm of Al, Cd and Pb, respectively, in the diet containing 3% CKD. Kidney, liver and bone ash concentrations of these three minerals were not increased by CKD, and typical toxicity signs were absent. It is concluded that CKD may contain one or more factors that interfere with normal bone metabolism in growing pigs when the diet contains 3.0% CKD.

Methane generation has been proposed as a means of swine waste disposal. As a secondary treatment to recover nitrogen, carbon and other nutrients from the effluent of a methane generator, Arthrospira platensis(a blue-green alga also known as Spirulina) was grown and its nutritive value determined. This alga contained 55 to 61% crude protein and was easy to harvest. Three indoor culture ponds of .65 M2were designed and built. The ponds consisted of a bottomless wooden frame lined with a polyethylene sheet resting on a table top. Culture medium was kept circulating by a special aerator. An inorganic medium was evaluated. When algal growth reached a saturation point, there was still 70% of N03—and 11% of HCO3—left unused in the medium. Swine waste fermented at a hydraulic retention time of 10 days gave the highest ratio (2.3:1) of NH3-N to TKN (about 70% NH3-N). NH3seemed to support best the growth of algae, when the effluent was slowly infused. Organic acids in the effluent also provided a good source of carbon, a limiting factor when algae were intensively grown. Under the light intensity of 500 footcandles, Arthrospirayielded about 5 g/M2/day. A sample containing 2,038 mg of NH3-N produced 16,250 mg of dry algae, containing 9,750 mg protein or 1,560 mg N, giving an efficiency of nitrogen recovery of 76%. The protein of Arthrospira platensisshowed a PER of 2.25, apparent nitrogen digestibility of 76.7% and biological value of 67.7%; no toxic effects were noted.

Two experiments were completed with a total of 54 5- to 7-week-old weanling Yorkshire pigs to determine (Experiment 1) the tissue retention of dietary selenium (Se) present in white sweet clover (Melilotus alba) relative to that provided as sodium selenite (Na2SeO3) and (Experiment 2) the tissue retention and liver distribution of Se present in fly ash incorporated into the diet.In Experiment 1, groups of four pigs each were randomly allotted to corn-soybean meal-type diets containing 5 or 10% white sweet clover grown either in low Se soil (.03 ppm Se in clover) or on fly ash (70 ppm Se in clover). Na2SeO3was added to the low Se clover diets to provide 0, 3.5 or 7.0 ppm of Se. Se concentrations of kidney, liver and skeletal muscle after 61 days were increased more by fly-ash grown sweet clover than by Na2SeO3, but blood Se was increased more by Na2SeO3. No histopathological lesions were found in liver, kidney, heart, pancreas or skeletal muscle. Diets had no effect on weight gain or feed to gain ratio.In Experiment 2, 30 pigs were fed from weaning to 92 kg slaughter weight on a corn soybean meal-type diet containing 0, 1, 2, 4 or 8% fly ash (5.7 ppm Se). Fly ash had no effect on weight gain and no histopathological lesions were found in heart, liver, kidney, pancreas or skeletal muscle. Tissue Se concentrations increased progressively with graded levels of fly ash in the diet. Distribution of Se in eight different sites in the liver was uniform. It is concluded that Se supplied in the diet as a component of fly ash or of white sweet clover grown on fly ash (probably as a constituent of seleno-amino acids) is absorbed and utilized for tissue deposition by the pig. The toxicological potency of clover-borne Se and its ability to alleviate vitamin E - Se deficiency signs relative to that of Na2SeO3remain unknown.

The objective was to study control of mature size by characterizing metacarpal growth plate closure in relation to relevant bone growth-regulating hormones in two breeds exhibiting distinct differences in mature frame size. Thirty-four Suffolk and 34 Dorset ram lambs were slaughtered in pairs within breed at birth, weaning and monthly intervals until 420 d and then bimonthly to 600 d. Plasma growth hormone was depressed to undetectable levels due to the high-energy, ad libitum-fed diet. Plasma insulin-like growth factor-I (IGF-I) rose over the growth period from 116 ng/ml (newborn Suffolk) to a high of 451 ng/ml (420-d Dorset); it appeared to peak at approximately 400 d and then declined to a stable level. Dorsets consistently exhibited higher IGF-I levels. The thyroid hormones exhibited no apparent age association. An age-associated rise was detected for testosterone, but not for estradiol. Mature metacarpal lengths were estimated to be 147.2 and 127.4 mm for Suffolks and Dorsets, respectively. Ninety-five percent of mature length was attained in Suffolks by 226 d and in Dorsets by 165 d. Growth plates, however, did not begin to appear closed until 390 d and closure was not complete in all animals until 480 d, suggesting that metacarpal growth rate was dissociated temporally from growth plate closure. Although growth plate closure likely is controlled by the endocrine system, there were no apparent relationships between circulating hormones and growth plate width, age at closure or zonal divisions within the growth plate, suggesting that the growth plate experiences a very different hormonal environment than what can be measured in the circulating blood.

Twenty-four weanling Yorkshire pigs were used in a 2 × 2 × 2 factorial arrangement of treatments to determine their response to high levels of dietary lead (Pb) (1,000 ppm) and zinc (Zn) (4,000 ppm) (as lead acetate and zinc oxide), to investigate the influence of high dietary calcium (Ca) (1.1%) on the biochemical and morphological manifestations of Pb and Zn toxicity, and to determine the effect of excess Zn on Pb toxicity. Clinical signs of Pb toxicity included behavioral changes, lameness, and anorexia. Pb content of blood, soft tissues, and bone was increased markedly by 1,000 ppm Pb in the diet during the 13-week experiment. Zn and Pb fed together, as compared with Pb alone, tended to increase Pb levels in blood, soft tissues, and bone and to enhance the toxic effects of Pb as shown by reduced weight gains, severe clinical signs, and pathological changes. High Ca reduced blood and bone Zn and Pb concentrations. The results indicate that high dietary Ca has a protective effect against the adverse effects of diet Pb and Zn, and that Zn aggravates Pb toxicity in growing pigs.

Cestrum diurnum(day-blooming jessamine) has been proposed to cause calcinosis in horses and cattle in Florida. The present studies investigated some physiological properties of the plant, using the chick as the experimental animal. The inclusion of dried leaf powder in a rechitogenic diet restored intestinal calcium-binding protein synthesis (CaBP) and increased calcium absorption in the cholecalciferol-deficient chick. The estimated level of cholecalciferol-equivalents in the dried leaf was about 30,000 to 35,000 IU/kg. Most of the activity was extractable with methanol:chloroform (2:1), indicating that the major cholecalciferol-like component in C. diurnumwas different from the water soluble factor(s) in Solanum malacoxylon. The time course of effect of C. diurnumextract in rachitic chicks was similar to that of 1,25-dihydroxycholecalciferol but the former had a longer lag time. The strontium fed chick, in which the kidney 25-hydroxycholecalciferol-1α-hydroxylase is inhibited, responded to C. diurnumextract, confirming the 1α, 25-dihydroxycholecalciferol-like character of the Cestrumfactor. The extract also appeared to interact with the intestinal 1α,25-dihydroxycholecalciferol cytosol receptor although this observation is preliminary. These findings indicate that the 1α,25-dihydroxycholecalciferol-like principle in C. diurnummay cause excessive calcium and phosphate absorption leading to calcinosis.

The localization of a plasma membrane calcium pump in the oviduct of the laying hen was investigated by immunohistochemical techniques, utilizing a monoclonal antibody (5F10) produced against the human erythrocyte calcium pump. This antibody was shown to react with an epitope of the pump in oviductal tissue, and prominent staining was observed on the microvilli of the tubular gland cells of the hen shell gland (uterus) and the isthmus. The Ca2+ pump was not detectable in the infundibulum or the magnum. Calbindin-D28k, also localized by immunohistochemical means, was observed to be present in the tubular gland cells of the shell gland and the distal isthmus (adjacent to shell gland) but not in either the proximal isthmus (adjacent to the magnum), the magnum or the infundibulum. The localization of the Ca2+ pump in the oviduct corresponds to known sites of mineral deposition during egg shell formation. The distribution of calbindin-D28k differed, co-localizing with the Ca2+ pump in the shell gland and distal isthmus but not in the proximal isthmus. This might reflect a greater rate of active Ca2+ secretion in the distal isthmus and shell gland as compared to the proximal isthmus.