Mechanism of adhesion and detachment at the anterior end of Merizocotyle icopae (Monogenea: Monocotylidae) including ultrastructure of the anterior adhesive matrix.

The anterior adhesive mechanism was studied for Merizocotyle icopae (Monogenea: Monocotylidae). Adult anterior apertures can open and close. In addition, duct endings terminating within the apertures are everted or retracted depending on the stage of attachment. Adhesive in adults is synthesized from all 3 secretory types (rod-shaped, small and large spheroidal bodies) found within anterior apertures. All exit together and undergo mixing to produce the adhesive matrix, a process that depletes duct contents. A greater number of ducts carrying rod-shaped bodies is depleted than ducts containing spheroidal bodies which changes the ratio of secretory types present on detachment. Detachment involves elongation of duct endings and secretion of additional matrix as the worm pulls away from the substrate. The change in secretory type ratio putatively modifies the properties of the secreted matrix enabling detachment. Only after detachment do ducts refill. During attachment, individual secretory bodies undergo morphological changes. The larval and adult adhesive matrix differs. Anterior adhesive in oncomiracidia does not show fibres with banding whereas banded fibres comprise a large part of adult adhesive. The data suggest that this is the result of adult spheroidal secretions modifying the way in which the adult adhesive matrix forms.

Mechanism of adhesion and detachment at the anterior end of Neoheterocotyle rhinobatidis and Troglocephalus rhinobatidis (Monogenea: Monopisthocotylea: Monocotylidae).

The anterior adhesion and detachment mechanisms observed for Neoheterocotyle rhinobatidis and Troglocephalus rhinobatidis (Monogenea: Monocotylidae) appear similar to those observed for the two other monopisthocotylean monogenean species with anterior apertures for which published data are available. This supports the theory that monogeneans with apertures may utilise a common mechanism. Adult anterior apertures can open and close and duct endings can evert during the adhesion phase and retract during detachment and searching behaviour. The adhesive is comprised of two secretory types, rod-shaped and spheroidal bodies, found within anterior apertures. These exit together and undergo mixing to produce the adhesive matrix in which elongate membranes from rod-shaped bodies are seen intermixed with a granular electrondense matrix. The morphology of the adhesive matrix differs from that found for some other monogenean taxa. Anterior detachment by these monocotylids appears to involve a depletion of rod-shaped bodies in ducts and mechanical withdrawal of the anterior end.

A comparison of the anterior adhesive system in the oncomiracidium and adult of the monogenean parasite Menizocotyle icopae (Monocotylidae).

The anterior adhesive system of the oncomiracidium and adult of Merizocotyle icopae (Monogenea: Monocotylidae) were compared. The oncomiracidium has one ventrally placed aperture on either side of the head near the anterior extremity. In the adult, there are three ventrally placed apertures on either side of the head region. Both systems have three types of electron-dense secretory bodies opening into each aperture. A rod-shaped secretion (S1) and a small electron dense ovoid secretion (S2) are common to larvae and adults. The third secretion type differs: in adults, it is a large, spherical (S3) type but in larvae, it is an ovoid (S4) body. S4 bodies do occur in adults, but appear to be secreted as a general body secretion. An additional anteromedian secretion (S5) is also present in the oncomiracidium, but is not secreted into the anterior apertures. Homology and function of secretions are discussed.

Liquid diets fed hourly to pigs weaned at 19 days of age and exposed to rotavirus (weanling diarrhea).

Five diets were tested for their capacity to promote weight gains in newly-weaned, 19-d-old, rotavirus-exposed pigs. The diets were tested under conditions designed to minimize the stress of weaning. That is, rotavirus-exposed pigs were moved at weaning to an isolation unit, caged individually and fed hourly liquid diets that were high (approximately 26%) and low in protein (approximately 11%). In all experiments, pigs experienced postweaning rotavirus-associated diarrhea and depression in rate of gain. Pigs grew faster: when fed diets high in protein (approximately 26% protein) vs low in protein (approximately 11% protein) and when fed diets containing cows' milk proteins vs proteins from soybean flour. A diet containing antibodies to rotavirus did not ameliorate the weanling diarrhea.

Effect of dietary nickel on growth, urease activity, blood parameters and tissue mineral concentrations in the neonatal pig.

Day-old pigs were individually fed a low nickel (0.16 ppm) liquid milk-based diet supplemented with either 0, 5 or 25 ppm nickel on a dry matter basis for a 21-day period. At the end of the liquid feeding period, five pigs per treatment were killed, and the remaining five were fed a dried skim milk-based diet (0.12 ppm nickel) with similar levels of added nickel for an additional 28 days. Dietary nickel did not affect animal gain, liver cholesterol, serum protein concentrations or bacterial urease activity in the gastrointestinal tract. The addition of 5 ppm nickel to the basal dry diet reduced ammonia concentrations in the cecum by 33%. Pigs receiving the high level of nickel had decreased serum alkaline phosphatase and increased serum glucose at 49 days, compared to controls. Animals receiving 5 ppm nickel had higher liver iron and zinc concentrations than controls at 21 days but not at 49 days. Control pigs had lower kidney and lung nickel concentrations than animals receiving 5 ppm nickel at 21 days but not at 49 days. Increasing dietary nickel from 5 to 25 ppm resulted in increased concentrations of nickel in serum, kidney, lung, spleen and muscle. These results suggest that 0.12-0.16 ppm nickel is adequate for growth of neonatal pigs fed milk-based diets. However, additional nickel may improve the iron and zinc status of the young pig.

The natural history of painful diabetic neuropathy--a 4-year study.

Thirty-nine patients with painful diabetic peripheral neuropathy were selected for a follow-up study to determine the natural history of this condition. Symptoms, motor conduction velocities (MCV) and ankle pressure indices were recorded at the initial assessment and after a mean study period of 4.7 years. Thirty-six patients completed the study and showed no significant changes in symptoms, but there was a significant fall in median nerve MCV. It is concluded that symptoms of established diabetic neuropathy persist for several years, and the changes in MCV may reflect continuing deterioration in nerve function.

Effect of feeding fat and altering weaning schedule on rebreeding in primiparous sows.

Primiparous sows that farrowed on a commercial farm during late summer in 1980 (n = 65) or late winter in 1981 (n = 62) and lactated 3 to 4 wk were used. Sows were assigned in a factorial experiment to one of two lactation diets (control or 10% fat-supplemented) and one of three periods (0, 2 or 5 d) of early weaning of the heaviest one-half of the litter. Days from weaning to estrus averaged 16.7 +/- 1.5 and 8.7 +/- 1.6 in summer and winter, respectively, and the season X diet interaction was significant for days from weaning to estrus and percentage of sows that exhibited estrus after weaning. In summer, supplementing diets with fat reduced the weaning-to-estrus interval from 20.9 +/- 2.1 to 12.6 +/- 2.1 d and increased percentage of sows in estrus by 10 d postweaning from 34 to 59. In winter, days from weaning to estrus tended to be greater and percentage of sows in estrus by 10 d postweaning tended to be less in sows fed fat-supplemented diets (10.3 +/- 2.5, 74%) than in sows fed control diets (7.1 +/- 2.9, 82%). Over both seasons, weaning one-half the litter 2 d early (2-d group) increased the percentage of sows in estrus by 10 d after weaning (77%) compared with 5-d (58%) or 0-d (51%) groups. Total litter weight at weaning was not affected by season, diet or days with one-half litter. However, piglets of lightest weight remaining on sows two or five extra days gained .09 +/- .03 kg/d more than lightest weight pigs in control (0-d) litters over the same interval. Early weaning of heaviest pigs may improve reproductive performance of primiparous sows in summer and winter, while supplementing lactation diets with fat may improve performance in summer, when weaning-to-estrus interval is longer than in winter.

The development of digestive capacity in young pigs: effects of weaning regimen and dietary treatment.

In Exp. 1, 24 crossbred pigs were weaned at 21 d of age to either a 24% milk protein diet or a 24% soy protein diet, both of which were fed hourly in liquid form. In Exp. 2, 45 crossbred pigs were weaned at 21 d of age to either a 24% milk protein diet fed hourly in liquid form, the same diet fed ad libitum in dry form or a 24% protein, corn-soybean meal diet fed ad libitum in dry form. Pigs were killed at 7 or 14 d postweaning in Exp. 1 and 7, 14 or 21 d postweaning in Exp. 2. In both experiments, pigs fed milk based diets had faster weight gains and more efficient feed conversion ratios than pigs fed diets containing soy protein. All data are expressed as units per kilogram body weight. Pigs fed a soy protein diet tended to have a greater intestinal length than pigs fed milk protein diets. Growth of the pancreas in relation to body weight was greater in pigs fed diets containing soy protein than in pigs fed milk protein. Pigs fed a soy protein diet tended to have greater trypsin and chymotrypsin activities in the intestinal contents and lower activities in the pancreas than did pigs fed milk-based diets. These results suggest that soy-containing diets caused a greater secretion of trypsin ad chymotrypsin into the intestine than did milk-containing diets.

Ammonium polyphosphate as a source of phosphorus and nonprotein nitrogen for monogastrics.

Ammonium polyphosphate (APP) was substituted for 0, 50 and 100% of the P supplied by defluorinated rock phosphate (DRP) in corn-soybean meal diets for growing rats and growing-finishing (G-F) pigs. The diets were formulated to contain 10% protein, .75% Ca and .60% P. Two-thirds of the P in the control diet was supplied by DRP. Replacement of 50 or 100% of the DRP with APP increased the dietary N by 7.25 and 14.5%, respectively. To evaluate nonprotein N (NPN) utilization, we used ammonium chloride (NH4Cl) to provide a level of N equivalent to that supplied by APP when it replaced 100% of the P supplied by DRP. These four treatments were repeated with supplementation of limiting amino acids (L-lysine, L-tryptophan and DL-methionine. Daily feed intake, rate of gain and feed:gain (F:G) of rats and G-F pigs were not influenced (P greater than .05) by the substitution of APP for DRP as a P source in corn-soybean meal diets with or without supplemental amino acids. F:G was improved (P less than .05) by the addition of limiting amino acids to diets for pigs, and a similar trend occurred in rats. The addition of NH4Cl to the 10% protein diets as a source of NPN resulted in no observable benefit for growing rats or G-F pigs. Percentages of ham and loin, percentages of bone ash and P content of the bone ash in pigs were not influenced by the dietary treatments.

Nutrition and management of early weaned pigs: effect of increased nutrient concentrations and (or) supplemental liquid feeding.

Four experiments involving a total of 304 crossbred pigs weaned at 3 to 4 weeks of age were conducted to examine the effect of feeding supplemental liquid milk two to three times daily at weaning and (or) of altering the nutrient composition of the weaning diet. In addition, the effects on postweaning performance of preconditioning young pigs to supplemental milk feeding in the farrowing house were determined. Performance immediately postweaning was poor and was characterized by low weight gains and low feed intakes for approximately 7 days. Increasing the protein and (or) energy concentrations in the weaning diet had no beneficial effect on pig performance in Exp. 1. Feeding supplemental cow's milk three times daily for 4 days postweaning and (or) adding fat to the dry weaning diet also had no beneficial effect on pig performance in Exp. 2. An added milk product to the diet did tend to improve feed efficiency in this experiment. In the third experiment, performance was not affected by supplemental liquid milk feeding three times daily for 7 days and twice daily for an additional 7 days. Additions of 30% nonfat dried milk to the dry diet offered ad libitum did result in improvement in pig performance. Preconditioning of young pigs to supplemental liquid feeding while still nursing the sow resulted in no beneficial response in pig performance immediately postweaning in Exp. 4.

Fluoride in treated sewage and in rain and snow.

The liquid effluent of a sewage treatment plan contained 1.21 ppm ionic and total fluoride, which was higher than 1.0 ppm fluoride in the fluoridated public water supply. The discharge of the effluent into a river did not greatly raise the fluoride content of the river water because of dilution and other factors. The semisolid waste of sewage treatment also contained fluoride, but very little was volatilized on burning. Rain and snow were found to contain detectable quantities of fluoride, and the fluoride content of snow increased markedly during exposure to an urban environment.

Influence of dietary fluoride restriction on regulation of plasma nd soft tissue fluoride contents.

The adjustments in total fluoride concentration in plasma, bones, liver, and muscle were examined when rats were given a diet of very low fluoride content following a dietary regimen of elevated fluoride intake. The animals received a diet containing 34 ppm of fluoride and water with 50 ppm added fluoride in the 28-day initial period and in the depletion period they were given a diet containing only 0.21 ppm of fluoride and distilled water. The findings indicated a 12-fold increase in the fluoride content of the humeri after 28 days of high-flurodie intake with a greater increment by the epiphyses than by the diaphyses. During 21 days of the depletion period the skeletal fluoride was reduced by only 7.7% indicating a marked retention of fluoride during processes of bone remodeling and growth. The plasma, muscle, and liver total fluoride contents were significantly increased at the end of the period of high-fluoride intake, but these concentrations were found to be restored to base-line levels in 3-7 days of the depletion period. By comparison of the distribution of total fluoride with injected radiofluoride between tissue and plasma waters, it was concluded that muscle and liver contain bound fluoride that does not exchange completely with ionic fluoride.