Apparent digestibility of a debranched amylopectin-lipid complex and resistant starch incorporated into enteral formulas fed to ileal-cannulated dogs1

The purpose of this study was to evaluate apparent digestibility in ileal-cannulated dogs fed enteral diets containing a debranched amylopectin-lipid complex (V-complex) or resistant starch. Six ileal-cannulated dogs were randomized into a replicated 3 x 3 Latin square design for determination of digestibility of three experimental treatments. Dietary treatments were as follows: 1) control; 2) V-complex; and 3) resistant starch. Diets were similar in chemical composition. Apparent digestibility of dry matter (DM), organic matter (OM) and carbohydrate by dogs fed the control diet was higher (P < 0.05) than for dogs consuming the other diets. Mean apparent digestibilities of carbohydrate for the control, V-complex and resistant starch diets were 89, 76 and 43%, respectively. Both DM and carbohydrate digestibility were lower (P < 0.05) for resistant starch compared with V-complex. Fecal dry and wet weights for dogs fed the control diet were lower (P < 0.05) than for those receiving either the resistant starch or V-complex treatments. Dogs fed the V-complex diet produced approximately 90 g less feces per day than dogs fed resistant starch. Dietary incorporation of V-complex to replace traditional carbohydrates may be beneficial for diabetic patients because of the decreased digestibility and subsequent glucose absorption rate. Furthermore, incorporation of resistant starch into enteral formulas may improve gastrointestinal tract health status as a result of increased fecal bulk, potential dilution of toxins in the intestinal lumen and greater production of short-chain fatty acids.     

Acute dietary PCPA treatment decreases the KD of brain [3H]5-HT binding in rainbow trout, Oncorhynchus mykiss, fed a high carbohydrate diet

Two experiments were conducted to determine the effect of dietary PCPA on brain [3H]5-HT binding in rainbow trout. [3H]5-HT binding was quantitatively similar to that observed in mammalian species. Dietary treatment with PCPA had no effect on the Bmax of [3H]5-HT binding in either experiment while the KD was decreased in Experiment 1. These results demonstrate that [3H]5-HT binding affinity is increased following short term inhibition of 5-HT synthesis by PCPA in rainbow trout.     

Conversion ratio of tryptophan to niacin in rats fed a vitamin B1-free diet

Patients with persistent uterine bleeding that is unresponsive to conservative therapy may opt for endometrial ablation over total hysterectomy because of concerns over subsequent sexual dysfunction or other nonclinical issues. Twelve such women with healthy cervices who failed endometrial ablation, and eight candidates for ablation were offered subtotal vaginal hysterectomy as a definitive primary surgical intervention instead of endometrial ablation. Our experience suggests the safety and utility of subtotal vaginal hysterectomy in properly selected patients. Randomized, comparative studies of this technique as an alternative to hysteroscopic ablation or resection may be warranted.     

Occurrence of aflatoxins, fumonisin B1, and zearalenone in foods and feeds in Botswana

Sorghum and maize form the main dietary staple foods in Botswana. Other products such as peanuts, peanut butter, phane (an edible larval stage of an emperor moth Imbrasia belina Westwood), and pulses (cowpeas and beans) are also widely used as food and for the manufacture of feeds. These important food and feed commodities were analyzed for the presence of aflatoxins, fumonisin B1, and zearalenone. Aflatoxins were detected in 40% of the samples analyzed. The concentration of total aflatoxins ranged from 0.1 to 64 microg/kg. The mean concentration ranged from 0.3 microg/kg in sorghum to 23 microg/kg in peanut butter. Peanut butter samples were the most contaminated (71%). No aflatoxins were detected in maize. Fumonisin B1 was detected in 36% of the samples. Maize samples were the most contaminated (85% of the samples) with the concentration ranging from 20 to 1,270 microg/kg. No fumonisin B1 was detected in peanuts, phane, and beans. Zearalenone was only found in 2.6% of the samples analyzed at 40 microg/kg. Aflatoxins were the most common toxins detected in foods and feeds in Botswana. However, fumonisin B1 was more prevalent in maize than aflatoxins or zearalenone.     

The use of the chicken embryo screening test and brine shrimp (Artemia salina) bioassays to assess the toxicity of fumonisin B1 mycotoxin

Chicken embryos and brine shrimp naulpii were utilized in short-term toxicity bioassays to assess their sensitivity to the mycotoxin fumonisin B1 (FB1). Fertile chicken eggs (Cobb x) were dosed with FB1 on day 2 of incubation by the injection of 100 microliters of aqueous solution into the air space of each egg. Eggs were incubated with mechanical rotation until hatch, at which time mortality was assessed. Probit transformation of the mortality data produced a linear line of best fit (P < 0.05), from which an LD50 of 52 micrograms FB1/egg, equivalent to a concentration of 1.3 microns hatched in artificial seawater and exposed to FB1 in an optimized 96-well plate assay with a 48 hr mortality endpoint. Probit transformation of the mortality data resulted in an LC50 of 1.7 microns FB1, or 1.2 micrograms FB1/ml. Thus, at the cellular level, both bioassays appeared sensitive to FB1; however, from the standpoint of use as a screening assay, the chicken embryo bioassay is limited by the relatively high dose of FB1 required per egg. It is anticipated that the design and simplicity of the brine shrimp bioassay will accommodate screening for FB1 toxicity in contaminated samples.     

Measurement of antibacterial activities of T-2 toxin, deoxynivalenol, ochratoxin A, aflatoxin B1 and fumonisin B1 using microtitration tray-based turbidimetric techniques

Various mycotoxins were tested for their antibacterial activity by evaluating growth delays using a fully automated microturbidmetric method. Ten different strains of the genera Escherichia, Streptococcus, Staphylococcus, Yersinia, Salmonella, Erysipelothrix and Lactobacillus were used as test micro-organisms. T-2 toxin, deoxynivalenol (DON), ochratoxin A (OTA), aflatoxin B1 (AFB1) and fumonisin B1 (FB1) were used as representative mycotoxins. The inhibitory effect in vitro was defined as the difference between the growth rate without mycotoxins and the growth rate in the presence of a mycotoxin. Among the tested strains, Streptococcus agalactiae was found to be sensitive to all the toxins, with the exception of OTA. T-2 toxin and FB1 were the most effective in slowing down the growth of Staphylococcus aureus. AFB1 affected the growth of Yersinia enterocolitica. The growth rate of Escherichia coli and Salmonella infantis was decreased by FB1. Among the bacterial strains used in this study, only the growth of Erysipelothrix rhusiopathiae was inhibited by OTA. Thus, using appropriate tester strains it should be possible to set up a broad-range microtubidimetry assay for individual mycotoxin screening in vitro. We concluded that the microtitration technique provides a rapid, convenient and high-throughput capacity system to analyse bacteria-mycotoxin interactions.     

Yeasts isolated from the intestine of rainbow trout adhere to and grow in intestinal mucus

The hyaline layer of echinoderm embryos is an extraembryonic matrix that functions as a substrate for cell adhesion through early development. The major constituent of the hyaline layer is the protein hyalin, a fibrillar glycoprotein of approximately 330 kDa that multimerizes in the presence of calcium. Here we provide a molecular characterization of hyalin and identify a region of the protein that is important for its function in cell adhesion. Partial hyalin cDNAs were identified from two sea urchin species, Strongylocentrotus purpuratus and Lytechinus variegatus, by screening expression libraries with monoclonal antibodies to hyalin. The cDNAs each encode a tandemly arranged series of conserved repeats averaging 84 amino acids. These hyalin repeats are as similar between the two species as they are to repeats within each species, suggesting a strong functional conservation. Analysis of this repeat shows that it is a unique sequence within the GenBank database with only weak similarity to mucoid protein sequences. The hyalin mRNA is approximately 12 kb in length and is present in developing oocytes coincident with the appearance of cortical granules, the vesicle in which the hyalin protein is specifically packaged. The mRNA is present throughout oogenesis but is rapidly lost at oocyte maturation so that eggs and early embryos have no detectable hyalin mRNA. The hyalin protein, however, remains at relatively constant levels throughout development. Thus, all the hyalin protein present during early development, when no RNA is detectable, is maternally derived and exocytosed from cortical granules at fertilization. Hyalin mRNA reaccumulates in embryos beginning at the mesenchyme blastula stage; a RNA gel blot and in situ hybridization analysis of gastrulae and larvae shows a progressive confinement of hyalin mRNA to the aboral ectoderm. Recombinant hyalin containing the tandem repeat region of the protein was expressed in bacteria and is shown to serve as an adhesive substrate, almost equal to that of native hyalin, in cell adhesion assays. This adhesive activity is partially blocked by dilute hyalin monoclonal antibody Tg-HYL to the same extent as that for native hyalin. Thus, this hyalin repeat region appears to contain the ligand for the hyalin cell surface receptor. These data help explain some of the classic functions ascribed to the hyalin protein in early development and now enable investigators to focus on the mechanisms of cell interactions with the hyaline layer.     

Influence of fumonisin B1, present in Fusarium moniliforme culture material, and T-2 toxin on turkey poults

Diets containing 300 mg fumonisin B1 (FB1)/kg of feed and 5 mg T-2 toxin/kg of feed singly or in combination were fed to female turkey poults (Nicholas Large White) from day of hatch to 21 d of age. When compared with controls, 21-d body weight gains were reduced 21% by FB1, 26% by T-2, and 47% by the combination. the efficiency of feed utilization was adversely affected by FB1 and the combination of FB1 and T-2. Relative weights (grams/100 g BW) of the liver and gizzard were increased in poults fed the FB1 and the combination diets; whereas, the relative weight of the pancreas was increased in all treated groups. All poults were scored for oral lesions using a scale of 1 to 4 (1 = no visible lesions, 4 = severe lesions). Oral lesions were present in all poults fed the T-2 diet (average score of 3.29) or the combination diet (average score of 3.54). Serum concentration of cholesterol was decreased and lactate dehydrogenase activity was increased in poults fed the FB1 and combination diets. The activity of aspartate aminotransferase and the values for red blood cells, hemoglobin, and hematocrit were increased only in poults fed the combination diet. Inorganic phosphorus concentration was decreased only in poults fed the combination diet. The increased toxicity in poults fed the combination diet for most variables can best be described as additive, although some variables not altered by FB1 or T-2 singly were significantly affected by the combination, indicating that the combination may pose a potentially greater problem to the turkey industry than either of the mycotoxins individually.     

The influence of dietary salt and energy on the response to low pH in juvenile rainbow trout

This study evaluated the role of diet, specifically the relative importance of salt content versus energy content, in the response of juvenile rainbow trout to environmental acid stress in soft water ([Ca2+] = 0.057 mmol L-1, [Na+] = 0.047 mmol L-1). Diets were formulated at two energy levels (regular, 16.3 MJ kg-1, and low, 9.8 MJ kg-1) and two levels of NaCl (regular, approximately 263 mmol kg-1, and low, approximately 64 mmol kg-1), yielding four treatment combinations, each fed at a ration of 0.6% body weight d-1. A fifth group of fish was not fed during the experiment. All groups were subjected to an initial acid challenge (24 h at pH 5.0 plus 12 h at pH 4.0), followed by 28 d of exposure to pH 5.2. Following the initial acid challenge, typical ionoregulatory disturbances were seen, but most effects had attenuated or disappeared by day 20 of chronic low-pH exposure. However, after 28 d, fish fed the regular-salt diets maintained the restored ionic homeostasis, whereas those fed low-salt diets did not, regardless of the energy content of the diet. Growth and food conversion efficiency were greatest in trout fed the regular-energy/regular-salt diet, negative in fish fed the low-energy/regular-salt diet, and intermediate in trout on the other diets; starved fish lost weight. Fish maintained on the regular-energy/low-salt diet exhibited the most deleterious effects, including elevated cortisol levels and a 4.1% d-1 mortality rate. Fish fed the low-energy/low-salt diet, those fed regular-salt diets, and starved fish were not as adversely affected by the acid stress. Following a regular-energy meal, fish tended to exhibit an elevated rate of oxygen consumption, but this did not occur after a low-energy meal, regardless of its salt content. Elevated oxygen consumption may be accompanied by a loss of ions via the osmorespiratory compromise. We hypothesize that fish fed the regular-energy/low-salt diets were most deleteriously affected in an acidified environment because they were unable to replace increased branchial ion losses with dietary salts. These results indicate that it is the salt content of the food rather than the energy content that is critical in protecting against the deleterious effects of low pH.     

The effect of poly-L-lysine, amiloride and methyl-L-lysine on gill ion transport and permeability in the rainbow trout

The action of poly-L-lysine (PLL) on Na and Cl transport across freshwater fish gills was studied. Low concentration (10-6M) were added to the external medium for brief periods (1--5 min), then removed. During the next 20 min there was a rapid net loss of Na (117+/17 muEquiv[100 g]-1hr-1) and Cl (129+/17 muEquiv[100 g]-1hr-1). Both values are an order of magnitude larger than unidirectional effluxes in control fish. The efflux of both ions decreased to control values within 60 min after application and removal of PLL. In contrast, unidirectional influxes (JCl in and JNa in) were inhibited by about 40+ and showed no sign of returning to the original rates for 3 hr. Thus, PLL has two independent actions, causing a large increase in gill permeability which is reversible within an hour and apartial inhibition of influx which showed no sign of reversing for 2--3 hr. When PLL was applied for a longer period (60 min, the results were qualitatively similar but the permeability change was larger and persisted longer. These effects were compared with those of the small organic amines, amiloride and methyl-L-lysine. The latter inhibited JNa in, but there was not other similarity to PLL. Neither affected sodium efflux, not did they have any effect on Cl movements, in or out, across the gill. Inhibition of JNa in, was rapidly and completely reversible, and amiloride was shown to act by competing with Na for an entry site.     

Effect of citric acid supplements to a maize-soya diet on the in vitro availability of minerals, trace elements, and heavy metals

The aim of the present study was to evaluate the effect of increasing supplements of citric acid (CTA) on the in vitro availability of mineral (Ca, Mg), trace elements (Mn, Zn) and heavy metals (Pb, Cd). Phytaterich diets (0.8%) based on maize, soybean meal, corn starch and soybean oil (containing 5.0 g Ca, 1.2 g Mg, 50 mg Mn, 22 mg Zn, 10 mg Pb and 5 mg Cd per kg diet) were supplemented with 0, 1, 2, 3 and 4% of CTA. All diets were treated in a multi-enzyme in vitro system followed by equilibrium dialysis after peptic and pancreatic digestion. Under the conditions investigated, dietary addition of CTA enhanced dialysability of calcium, magnesium, manganese and zinc. Furthermore, a dose-dependent increase of lead and cadmium dialysability due to CTA supplementations was evident.     

The effect of size on the fast-start performance of rainbow trout Salmo cairdneri, and a consideration of piscivorous predator-prey interactions

The fast-start (acceleration) performance of seven groups of rainbow trout from 9-6 to 38-7 cm total length was measured in response to d.c. electric shock stimuli. Two fast-start kinematic patterns, L- and S-start were observed. In L-starts the body was bent into an L or U shape and a recoil turn normally accompanied acceleration. Free manoeuvre was not possible in L-starts without loss of speed. In S-starts the body was bent into an S-shape and fish accelerated without a recoil turn. The frequency of S-starts increased with size from 0 for the smallest fish to 60-65% for the largest fish. Acceleration turns were common. The radius of smallest turn for both fast-start patterns was proportional to length (L) with an overall radius of 0-17 L. The duration of the primary acceleration stages increased with size from 0-07 s for the group of smallest fish to 0-10 s for the group of largest fish. Acceleration rates were independent of size. The overall mean maximum rate was 3438 cm/s2 and the average value to the end of the primary acceleration movements was 1562 cm/s2. The distance covered and velocity attained after a given time for fish accelerating from rest were independent of size. The results are discussed in the context of interactions between a predator and prey fish following initial approach by the predator. It is concluded that the outcome of an interaction is likely to depend on reaction times of interacting fish responding to manoeuvres initiated by the predator or prey. The prey reaction time results in the performance of the predator exceeding that of the prey at any instant. The predator reaction time and predator error in responses to unpredictable prey manoeuvre are required for prey escape. It is predicted that a predator should strike the prey within 0-1 s if the fish are initially 5-15 cm apart as reported in the literature for predator-prey interactions. These distances would be increased for non-optimal prey escape behaviour and when the prey body was more compressed or depressed than the predator.     

Purification and partial characterization of 76 kDa transglutaminase in the egg envelope (chorion) of rainbow trout, Oncorhynchus mykiss

Transglutaminase (TGase), responsible for crosslinking between proteins, is known to be localized exclusively in the egg envelope (chorion) of rainbow trout, Oncorhynchus mykiss, and probably participates in the post-fertilization chorion hardening. We purified the TGase from unfertilized egg chorions by sequential chromatography using SP-Sepharose, Q-Sepharose, and TSK-gel G3000SWXL columns. The purified enzyme was a monomeric protein having the molecular mass of 76 kDa. It promoted incorporation of monodansyl-cadaverine into chorion protein and catalyzed the polymerization of chorion subunit proteins. The effect of various reagents suggested that the chorion TGase is a Ca2+-dependent SH-enzyme similar to the well-characterized TGases of various animals. The highest activity was observed at pH 6.0. The amines examined in the present study inhibited the TGase activity of the purified enzyme. However, they did not necessarily cause effective inhibition of its activity. These properties of the chorion TGase were essentially consistent with our previous observations on polymerization of chorion proteins, resulting in chorion hardening. We compared the amino acid composition of the purified TGase with those of the previously characterized TGases of fishes, such as chum salmon and red sea bream. The results suggest that the chorion 76 kDa TGase is not homologous with those liver TGases in terms of amino acid composition.     

Evaluation of the critical body burden concept based on inorganic and organic mercury toxicity to rainbow trout (Oncorhynchus mykiss)

Subadult rainbow trout (Oncorhynchus mykiss) were exposed to four waterborne concentrations each of 64-426 microg/L mercuric chloride (HgCl2) and 4-34 microg/L methylmercury chloride (CH3HgCl) until death to evaluate the critical body burden concept. Mean days to death for fish exposed to the highest and lowest concentrations of HgCl2 were 1 and 58 d, and 2 and > 100 d for fish exposed to CH3HgCl. Time to death was an important factor that influenced Hg tissue concentration, and was most evident among fish that died within a few days of exposure. Critical body burdens for Hg could be difficult to establish at the tissue level because no threshold concentrations were clearly indicated among the liver, kidney, spleen, brain, muscle, and gill that were monitored in this study. A critical burden for Hg was derived on a whole body basis for Hg in its organic form. An evaluation of this and other studies suggests whole body concentrations of 10-20 mg/kg Hg could be lethal to fish. Extrapolation from other studies indicate whole body concentrations of 1-5 mg/kg Hg could have chronic effects on fish and possibly other aquatic organisms. This concept could be used to assess the toxicological significance of chemical concentrations that are monitored in feral aquatic organisms. The tissue-based approach appears to have some advantages over current assessment protocols that focus on waterborne concentrations.     

Growth and development of the kidneys, heart and liver in S 5B/P1 and Osborne-Mendel rats fed high or low-fat diets

Male Osborne-Mendel (OM) and S 5B/P1 rats were overfed from birth to 24 or 105 days. The effects of feeding a diet with 44 per cent or 3 per cent (w/w) fat, supplementary feeding during the suckling period, and reduced litter size, on body weight and on the weight and cellularity of the heart, liver and kidneys were evaluated. Three overfeeding techniques were used: (1) feeding a high fat diet, (2) reducing litter size, (3) force-feeding from 1-24 days. The overfeeding technique which exerted the greatest effect on growth was feeding a high-fat diet. In comparison to OM rats that suckled dams fed the low-fat diet, body weight as well as organ weight, DNA, protein and lipid were significantly elevated in 24-day-old OM rats that suckled dams fed the high-fat diet. In comparison to OM rats not overfed, the organs of the rats fed the high-fat diet contained significantly more cells at both 24 and 105 days, except for the heart which by 105 days contained more protein, but not DNA. Liver weight and growth in S 5B/P1 rats was similar, regardless of dietary manipulation. Compared to S 5B/P1 rats that suckled dams fed the low-fat-diet, kidneys were 12 per cent larger at 24 days and 19 per cent larger at 105 days in rats that suckled dams fed the high-fat diet and were thereafter fed a high-fat diet. Hearts of the latter rats were larger than the former rats at 24 days, but not at 105 days.     

Alteration of milk fat by variation in the source and amount of starch in a total mixed diet fed to dairy cows

The effect on milk yield and composition of the supplementation of the diets of dairy cows with wheat or potato peelings was studied at three different starch intakes (< 5, 6, and > 7.5 kg/d) for dry matter intakes around 20 kg/d. Starch supply was varied using different dietary concentrations of corn silage. Trials were conducted using Latin square designs, and all cows were fed a total mixed diet composed of corn silage, grass silage, or both; soybean meal; a mixed meal with formaldehyde treatment; minerals; and one of the following energy concentrates: potato peelings or wheat. Dry matter and energy intakes varied significantly only at the low starch concentration; higher intakes were observed when the potato peelings were fed. Body weight, milk yield, true protein content, lactose content, and protein yield were not affected by treatment. Milk fat content was higher (+3.3 g/kg) when potato peelings were fed at the high starch concentration but was unaffected at the low and medium starch concentration. Slow degradation of starch from the potato peelings in the rumen could enhance a higher delivery of precursors of milk fat synthesis in the udder. The effect on fat yield differed among starch concentrations. Milk fat content appeared to decrease for cows fed diets containing quickly degradable starch at a starch intake > 7 kg/d.     

Effects of age and coion (K+ and Na+) on the toxicity of thiocyanate to rainbow trout (Oncorhynchus mykiss) during pulse or continuous exposure

An ophthalmic follow-up comprised 88 children aged 7-10 years who had regular screening for retinopathy of prematurity (ROP) after their pre-term delivery 1982-84. Mean values of birth weight and gestational age in the 88 were 1467 g and 31 weeks. Out of 28 with early evidence of ROP four had progressed to bilateral blindness; the remaining 24 had at least a corrected visual acuity of 0.4 at disposal. The corrected median binocular acuity for all 88 was 0.95; however, the cumulated frequency curve was significantly below a previously stated norm in full-terms. The same conclusion was valid for single eye vision. Within the material, the visual score of the 28 with early ROP was significantly lower than in the remaining 60 subjects. Ophthalmoscopy often showed tortuosity of vessels, but no specific central retinal or optic nerve lesion to explain the slight general depression of visual acuity, and opacities of media contributed in only two subjects. It is concluded, that very preterm delivery generally influences the potential for developing full visual acuity, also in individuals without evidence of early ROP. Evidence of CNS-damage negatively influenced visual acuity score.     

The comparative study of peroxidase activity and substrate binding properties of cytochrome P450 2B4 incorporated into phospholipid vesicles with the use of two different methods

The comparative study of peroxidase activities and substrate binding properties of cytochrome p450 2B4 in reconstituted vesicles prepared with the use of two different techniques, and microsomal cytochrome P450 was carried out. The data obtained show that the two types of cytochrome P450 2B4-containing proteoliposomes do not differ substantially from each other with respect to H2O2- or cumene hydroperoxide-dependent substrate hydroxylation activities as well as substrate binding properties of hemoprotein reconstituted. However, some parameters measured with proteoliposomal cytochrome P450 are markedly different from those measured with microsomal hemoprotein, suggesting the existence of conformational differences between the molecules of these two cytochromes or the differences in the depth of their immersion into lipid bilayer.     

Infusion of the serotonin1B (5-HT1B) agonist CP-93,129 into the parabrachial nucleus potently and selectively reduces food intake in rats

A case is described in which a child appeared for evaluation with marked gingival overgrowth, facial dysmorphism, and abdominal defects consistent with prune-belly syndrome. The relationship between this case and other reports of gingival enlargement are discussed. Coincidence of the oral, facial, and abdominal abnormalities has not been previously reported.