Effectiveness of sodium bentonite and two commercial products as aflatoxin absorbents in diets for broiler chickens

Three hundred day-old commercial broiler chicks were reared in 10 groups to examine the effects of indigenous sodium bentonite (SB) as a sodium bentonite simple, sodium bentonite + gention violet and sodium bentonite + acetic acid on two levels 0.5 and 1% of feed, along with two market products Sorbatox and Klinofeed on two levels of aflatoxin 0 and 100 mcg/kg. Each group was replicated three times. The aflatoxins (AF) were incorporated in a standard commercial broiler ration and fed to chicks for 6 week. Body weight and feed consumption was recorded weekly. At the end of the experiment two birds from each group were slaughtered to note the relative weight of heart, liver, gizzard and dressing percentage. Titre against Newcastle disease (ND) was monitored at day 21st, 28th, 35th and 42nd of the experiment.Statistical analysis indicated that aflatoxin in diet negatively affected (P<0.05) all the parameters. Chicks receiving aflatoxin-contaminated diet had suppressed body weight, feed consumption and FCR value, which was significantly improved with the addition of 0.5% simple sodium bentonite. The relative weight of liver (5.34%), heart (0.72%), gizzard (2.05%) and mortality (40%) increased significantly with the addition of 100 mcg/kg aflatoxin and were restored to 3.57, 0.57, 1.43 and 16.6%, respectively, with the dietary inclusion of 0.5% simple sodium bentonite. However, dressing percentage significantly decreased (51.7%) when diet (B) was supplemented with 100 mcg/kg aflatoxin as compared to the diet where no aflatoxin was added (diet A). The titre against Newcastle disease (ND) also showed poorest results by addition of aflatoxin which also improved by inclusion of 0.5% simple sodium bentonite. Addition of indigenous sodium bentonite gave overall better results than the market products and between two levels of indigenous sodium bentonite, 0.5% level gave better results than 1%.     

Toxic effects of fermented and unfermented sorghum meal diets naturally contaminated with mycotoxins

Male weanling rats fed diets containing fermented and unfermented tannin-free sorghum meals naturally contaminated with traces of ochratoxin A, zearalenone, and an unidentified toxic substance developed anorexia. Mean changes in body weight over a 28-day feeding period for rats fed fermented and unfermented sorghum meal and ANCR casein diets of 8% protein were -2.8, +13.8, and +100.5 g, respectively. Rats fed fermented sorghum meal developed alopecia; hematological findings showed a decreased mean corpuscular volume, hypochromic microcytosis, balanced leukopenia, and hypoproteinuria . Histological findings showed testicular hypoplasia of the germinal epithelium and no mature spermatozoa. Necrosis and mineralization in Henle's loop were also observed. No damage was apparent to the liver, cerebellum, cerebrum, spleen, or adrenal glands.     

The fate of aflatoxin in naturally contaminated corn during the ethanol fermentation

Corn naturally contaminated with aflatoxin was used as a substrate in the ethanol fermentation. Distribution of toxin in several process and recovery fractions was identified. Although little degradation of the mycotoxin occurred during fermentation, no toxin appeared in the distilled alcohol. As accumulation of toxin in spent grains represents a potential problem in use of the material as animal feed, several decontamination procedures were tested. Sodium hydroxide, ammonium hydroxide, sodium hypochlorite, and hydrogen peroxide were identified as efficient agents of toxin degradation.     

Toxic effects of fermented and unfermented sorghum meal diets naturally contaminated with mycotoxins.

Male weanling rats fed diets containing fermented and unfermented tannin-free sorghum meals naturally contaminated with traces of ochratoxin A, zearalenone, and an unidentified toxic substance developed anorexia. Mean changes in body weight over a 28-day feeding period for rats fed fermented and unfermented sorghum meal and ANCR casein diets of 8% protein were -2.8, +13.8, and +100.5 g, respectively. Rats fed fermented sorghum meal developed alopecia; hematological findings showed a decreased mean corpuscular volume, hypochromic microcytosis, balanced leukopenia, and hypoproteinuria . Histological findings showed testicular hypoplasia of the germinal epithelium and no mature spermatozoa. Necrosis and mineralization in Henle's loop were also observed. No damage was apparent to the liver, cerebellum, cerebrum, spleen, or adrenal glands.     

Effective heat inactivation of Mycobacterium avium subsp. paratuberculosis in raw milk contaminated with naturally infected feces

The effectiveness of high-temperature, short holding time (HTST) pasteurization and homogenization with respect to inactivation of Mycobacterium avium subsp. paratuberculosis was evaluated quantitatively. This allowed a detailed determination of inactivation kinetics. High concentrations of feces from cows with clinical symptoms of Johne's disease were used to contaminate raw milk in order to realistically mimic possible incidents most closely. Final M. avium subsp. paratuberculosis concentrations varying from 10(2) to 3.5 x 10(5) cells per ml raw milk were used. Heat treatments including industrial HTST were simulated on a pilot scale with 22 different time-temperature combinations, including 60 to 90 degrees C at holding (mean residence) times of 6 to 15 s. Following 72 degrees C and a holding time of 6 s, 70 degrees C for 10 and 15 s, or under more stringent conditions, no viable M. avium subsp. paratuberculosis cells were recovered, resulting in >4.2- to >7.1-fold reductions, depending on the original inoculum concentrations. Inactivation kinetic modeling of 69 quantitative data points yielded an E(a) of 305,635 J/mol and an lnk(0) of 107.2, corresponding to a D value of 1.2 s at 72 degrees C and a Z value of 7.7 degrees C. Homogenization did not significantly affect the inactivation. The conclusion can be drawn that HTST pasteurization conditions equal to 15 s at > or =72 degrees C result in a more-than-sevenfold reduction of M. avium subsp. paratuberculosis.     

Growth of spoilage mould and aflatoxin B1 production in naturally contaminated or artificially inoculated maize as influenced by moisture content under ambient tropical condition

Maize (cv. TSZB) samples were re-moistened to different moisture contents (m.c.s) of 13, 15, 17, 20, 25, 30 or 35% and stored with the natural microflora or sterilized before artificial inoculation with either single or mixed moulds (Aspergillus flavus, A. niger, Penicilium purpurogenum and Fusarium moniliforme) and evaluated for initiation time for moulding, fungal populations and aflatoxin B₁ production. Whereas the fungal populations of naturally contaminated maize of 13% m.c. decreased significantly with storage, 17 and 20% m.c. maize increased with the latter showing maximum of about log₁₀ 7 colony forming units (cfu g⁻¹). Of the samples (13, 15, 17 or 20% m.c. maize), only those of ≥20% m.c. showed hazardous levels (>20 ppb) of aflatoxin B₁ production. The 20% m.c. sample also showed a significant positive correlation (r = 0.92) between m.c. and fungal load but those of lower m.c.s exhibited poor correlations, probably reflecting the absence of changes in the m.c.s of the 13, 15 and 17% m.c. maize. Aflatoxin B₁ content of 25% m.c. maize increased with increase in inoculum concentration of A. flavus. Mixed mould inoculation of maize samples resulted in a reduction in aflatoxin concentration with co-cultures of A. flavus and P. purpurogenum showing the lowest production, while that inoculated with A. flavus alone (control) exhibiting the maximum production. Initiation time for moulding was most rapid in ≥20% m.c. maize irrespective of inoculum type, with A. flavus being the most invasive in singly inoculated samples. However, A flavus was most competitive in 20–30% m.c. maize inoculated with mixed moulds, while F. moniliformewas most competitive in the 35% m.c. maize.     

On the specific and unspecific effects of a polymeric glucomannan mycotoxin adsorbent on piglets when fed with uncontaminated or with Fusarium toxins contaminated diets

A 35-day feeding experiment was performed with weaned piglets (initial live weight of 7.7 +/- 1 kg) to test the effects of a Fusarium toxin contamination of the diet (4.44 mg deoxynivalenol [DON] per kg diet) compared to an uncontaminated control diet. Both diet types were fed either unsupplemented or supplemented with a polymeric glucomannan mycotoxin adsorbent (GMA) to examine the claimed efficacy of detoxification of this feed additive through unspecific performance parameters and the specific proof of the prevention of DON absorption. Feeding of the mycotoxin-contaminated diets resulted in a decrease in feed intake and live weight gain by 28% and 14% when compared to the control group. These effects were independent of GMA addition. Based on the lack of significant interactions between diet mycotoxin-contamination and GMA supplementation for the performance data, and because of the inefficiency of GMA in decreasing DON absorption, it was concluded that the supplementation of DON-contaminated piglet diets with GMA cannot be recommended as an effective tool for alleviation of adverse DON effects.     

On the specific and unspecific effects of a polymeric glucomannan mycotoxin adsorbent on piglets when fed with uncontaminated or with Fusarium toxins contaminated diets

Abstract

A 35-day feeding experiment was performed with weaned piglets (initial live weight of 7.7±1 kg) to test the effects of a Fusarium toxin contamination of the diet (4.44 mg deoxynivalenol [DON] per kg diet) compared to an uncontaminated control diet. Both diet types were fed either unsupplemented or supplemented with a polymeric glucomannan mycotoxin adsorbent (GMA) to examine the claimed efficacy of detoxification of this feed additive through unspecific performance parameters and the specific proof of the prevention of DON absorption. Feeding of the mycotoxin-contaminated diets resulted in a decrease in feed intake and live weight gain by 28% and 14% when compared to the control group. These effects were independent of GMA addition. Based on the lack of significant interactions between diet mycotoxin-contamination and GMA supplementation for the performance data, and because of the inefficiency of GMA in decreasing DON absorption, it was concluded that the supplementation of DON-contaminated piglet diets with GMA cannot be recommended as an effective tool for alleviation of adverse DON effects.     

Mutagenic effects of aflatoxin B-1 and G-1 on the Egyptian cotton leaf-worm,Spodoptera littoralis (Boisd.)

The aim of this study was to test infertility of the Egyptian cotton leaf-worm, Spodoptera littoralis. Three concentrations, 0.8, 1.6 and 2.0 g/ larva of aflatoxin B-1 and G-1 were applied to the final instar of the larval period. Both B-1 and G-1 induced mutagenic effects on spermatogenesis and morphogenesis which consequently reflected in infertility of Spodoptera littoralis. The phenomenon of mutagenicity was more obvious in larvae treated with G-1 rather than in those treated with B-1. The two analogues were also capable of inducing malformations in sperms. These abnormalities were transmitted to and inherited by the progeny.     

Feeding tests with ducklings,Turkey chicks and rabbits and the effects of aflatoxin on these animals

The effects of feeding animals with a toxic strain ofA. flavus was examined. The animals examined were ducklings, turkeys and rabbits. All of them showed loss of weight and mortality after feeding with aflatoxin.The livers of those animals showed that aflatoxin caused pathological changes. This damage of the liver is the lethal effect of the aflatoxin.

---

Zusammenfassung Die Wirkung der Fütterung von Tieren mit einem toxischen Stamm vonA. flavus wurde untersucht. Die Tiere sind Entchen, Truthähnchen und Hasen. Alle zeigten einen Gewichtverlust und eine Mortalität nach Aflatoxin-Fütterung. Die Leber der Tiere zeigte, daß Aflatoxin pathologische Veränderung herbeiführte. Die Leberschädigung ist die tötliche Wirkung des Aflatoxins.

---

---

Research supported by grant number FG-Is-161 of the United States Department of Agriculture to whom the author is indebted.     

The defensive role of latex in plants: detrimental effects on insects

The defensive role of the latex of Calotropis procera has recently been reported. In this study, latex proteins involved in detrimental effects on insects were evaluated on another important crop pest. The latex was fractionated to obtain its major protein fraction, which was then used to evaluate its insecticidal properties against Callosobruchus maculatus (Coleoptera: Bruchidae) in artificial bioassays. Laticifer proteins (LP) were investigated to characterize their action in such an activity. LP was highly insecticidal at doses as low as 0.1% (W/W). This effect was slightly augmented in F₁ generation reared in artificial seeds containing LP at similar proportions of F₀, but was fully reversed when F₁ developed in LP-free seeds. The insecticidal proteins were not retained in a chitin column, and did not lose their insecticidal activity, even after heat treatment or pronase digestion. However, these samples inhibited papain (EC 3.4.22.2) activity and gut proteases of C. maculatus larvae, and a reverse zymogram showed the presence of protein bands resistant to papain digestion. These activities were not observed in unheated LP as they were probably masked by abundant endogenous cysteine protease (EC 3.4.22.16) activity present in unheated LP. LP was resistant to proteolysis when assayed with C. maculatus gut extract. However, gut proteins of C. maculatus were digested when incubated with LP. These observations and the deleterious effects of LP upon C. maculatus, reinforce the hypothesis that laticifer fluids are involved in plant defense against insects and indicate C. procera latex to be a source of promising insecticidal proteins. The inhibitor of proteolysis present in the latex seems to be resistant to heat and proteolysis and is certainly involved in the detrimental effects observed.     

The role of adsorption in the elimination of aflatoxin B1 from contaminated media

Summary The mechanism involved in the disappearance of aflatoxin B₁ from liquid medium by fungus mycelium has been investigated.It is shown that mycelium and clay can adsorb aflatoxin dissolved in liquid media; in this way it is possible to detoxify contaminated solutions.From this observation, it is suggested that adsorption should be adopted as a new technique in the removal of aflatoxin from contaminated liquid foodstuffs.     

Two viruses of Heterobasidion confer beneficial,cryptic or detrimental effects to their hosts in different situations

We investigated the effects of two recently described dsRNA mycoviruses, HetRV3-ec1 and HetRV6-ab6, on Heterobasidion wood decay fungi. The viruses originally inhabited Heterobasidion ecrustosum and Heterobasidion abietinum, and were transferred in the laboratory into other Heterobasidion species. Isogenic virus-free and virus-infected Heterobasidion isolates were used to test the effects of these viruses on their hosts' growth rate and competitive ability against mycorrhizal and decay fungi (Paxillus involutus, Meliniomyces bicolor and Phlebiopsis gigantea). This study shows that: (i) a single virus strain confers different effects on different Heterobasidion host strains; and (ii) a single virus strain may have contrasting effects on the fitness of a single host isolate (ranging from no effect to harmful or beneficial) depending on environmental and ecological conditions. We also report for the first time on the antagonism of Helotiales belonging to the sub-group Rhizocyphus–Meliniomyces against Heterobasidion species.     

Chromatin diminution in the copepod Mesocyclops edax: diminution of tandemly repeated DNA families from somatic cells.

Chromatin diminution, i.e., the loss of selected chromosomal regions during the differentiation of early embryonic cells into somatic cells, has been described in taxa as varied as ciliates, copepods, insects, nematodes, and hagfish. The nature of the eliminated DNA has been extensively studied in ciliate, nematode, and hagfish species. However, the small size of copepods, which makes it difficult to obtain enough DNA from early embryonic cells for cloning and sequencing, has limited such studies. Here, to identify the sequences eliminated from the somatic cells of a copepod species that undergoes chromatin diminution, we randomly amplified DNA fragments from germ line and somatic line cells of Mesocyclops edax, a freshwater cyclopoid copepod. Of 47 randomly amplified germ line clones, 45 (96%) contained short, tandemly repeated sequences composed of either 2 bp CA-repeats, 8 bp CAAATAGA-repeats, or 9 bp CAAATTAAA-repeats. In contrast, of 83 randomly amplified somatic line clones, only 47 (57%) contained such short, tandemly repeated sequences. As previously observed in some nematode species, our results therefore show that there is partial elimination of chromosomal regions containing (CAAATAGA and CAAATTAAA) repeated sequences during the chromatin diminution observed in the somatic cells of M. edax. We speculate that chromatin diminution might have evolved repeatedly by recruitment of RNAi-related mechanisms to eliminate nonfunctional tandemly repeated DNA sequences from the somatic genome of some species.     

Levels of copper and zinc in diets for growing and finishing pigs can be reduced without detrimental effects on production and mineral status

One hundred and sixty pigs were used to evaluate dietary copper (Cu) and zinc (Zn) supplementation on performance, fecal mineral levels, body mineral status and carcass and meat quality. Diets differed in mineral form (MF) (Cu and Zn in the form of proteinate amino acid chelate (organic) or sulfate (inorganic)) and inclusion level (IL) (27 mg/kg of total Cu and 65 mg/kg of total Zn ('low') or 156 mg/kg of total Cu and 170 mg/kg of total Zn ('high')) according to a 2 × 2 factorial arrangement of treatments. Pigs were used from 25 to 107 kg body weight (BW) and fed their respective diets ad libitum. Blood and fecal samples were collected on days 14 and 77 of the experiment. Blood was analyzed for concentration of Cu and Zn, hemoglobin (Hb), Cu content of red blood cells (RBC Cu) and alkaline phosphatase (ALP) and feces for Cu and Zn concentration. Hot carcass weight (HCW) and backfat depth were measured at slaughter and indices of meat quality were assessed on a section of longissimus thoracis. Liver, kidney and bone samples were collected immediately after slaughter and liver and kidney were tested for Cu and Zn content, while bone was only tested for Zn. Over the entire experimental period (25 to 107 kg BW) no significant treatment differences in average daily gain (ADG) or average daily feed intake (ADFI) occurred; however, feed conversion ratio (FCR) was improved by the inclusion of proteinate amino acid chelate (P = 0.012). Copper and Zn concentrations in feces were in direct proportion to the IL in the diet. Blood mineral levels were within normal physiological ranges in all treatments and tissue Cu and Zn concentrations increased with dietary IL (P < 0.05). Results indicate that Cu and Zn fecal concentrations were reduced by approximately 6-fold for Cu and by 2.5-fold for Zn by feeding 27 mg/kg Cu and 65 mg/kg Zn, in either the proteinate amino acid chelate or the sulfate form, compared with a diet containing 156 mg/kg Cu and 170 mg/kg Zn. This decrease in total dietary Cu and Zn did not reduce performance or mineral status of pigs.     

Turnover of 125I-VLDL and 131I-LDL apolipoprotein B in rabbits fed diets containing casein or soy protein

Rabbits fed low-fat, cholesterol-free, semi-purified diets containing casein developed a marked hypercholesterolemia compared to rabbits fed a similar diet containing soy protein (plasma cholesterol 281 +/- 31 vs. 86 +/- 9 mg/dl; P less than 0.05). Turnover studies (three per dietary group) were carried out in which homologous 125I-labeled VLDL and 131I-labeled LDL were injected simultaneously into casein- (n = 8) or soy protein- (n = 9) fed rabbits. ApoB-specific activities were determined in VLDL, IDL and LDL isolated from the pooled plasma of two or three rabbits per dietary group. The production rate of VLDL apoB (1.20 +/- 0.3 vs. 1.09 +/- 0.1 mg/h per kg) was similar for the two dietary groups. The fractional catabolic rate of VLDL apoB was lower for the casein group (0.15 +/- 0.03 vs. 0.23 +/- 0.01.h-1; 0.05 less than P less than 0.10). Although the pool size of VLDL apoB was higher in the casein group (8 +/- 2 vs. 5 +/- 0.3 mg/kg), this value did not reach statistical significance. For LDL apoB, the increased pool size in casein-fed rabbits (30 +/- 5 vs. 5 +/- 1 mg/kg; P less than 0.01) was associated with a decreased fractional catabolic rate (0.03 +/- 0.005 vs. 0.08 +/- 0.008.h-1; P less than 0.01) and a 2-fold increase in the production rate of LDL apoB (1 +/- 0.3 vs. 0.4 +/- 0.06 mg/kg per h; 0.05 less than P less than 0.10) compared to rabbits fed soy protein. Analysis of precursor-product relationships between the various lipoprotein fractions showed that casein-fed rabbits synthesized a higher proportion of LDL apoB (95% +/- 2 vs. 67% +/- 2; P less than 0.001) independent of VLDL catabolism. These results support the concept that the hypercholesterolemia in casein-fed rabbits is associated with impaired LDL removal consistent with a down-regulation of LDL receptors. These changes do not occur when the casein is replaced by soy protein.     

Population continuity or population change: formation of the ancient Egyptian state

The origins of the ancient Egyptian state and its formation have received much attention through analysis of mortuary contexts, skeletal material, and trade. Genetic diversity was analyzed by studying craniometric variation within a series of six time-successive Egyptian populations in order to investigate the evidence for migration over the period of the development of social hierarchy and the Egyptian state. Craniometric variation, based upon 16 measurements, was assessed through principal components analysis, discriminant function analysis, and Mahalanobis D(2) matrix computation. Spatial and temporal relationships were assessed by Mantel and Partial Mantel tests. The results indicate overall population continuity over the Predynastic and early Dynastic, and high levels of genetic heterogeneity, thereby suggesting that state formation occurred as a mainly indigenous process. Nevertheless, significant differences were found in morphology between both geographically-pooled and cemetery-specific temporal groups, indicating that some migration occurred along the Egyptian Nile Valley over the periods studied.