The impact of natural helminth infections and supplementary protein on growth performance of free-range chickens on smallholder farms in El Sauce, Nicaragua

Three on-farm studies were conducted in Nicaragua during three consecutive years (1999–2001) to assess the impact of natural helminth infections on growth performance of free-range chickens aged 3–4 months. On all participating farms, half of the chickens were treated regularly with anthelmintics (Trifén avícola – a combined formulation of piperazine, phenothiazine and dichlorophen – or albendazole) to express the growth potential of non-infected birds, whereas the other half served as non-treated controls. In 1999, treated chickens had a 39% higher weight gain compared to the control group 6 weeks after the first treatment on 15 farms. In 2000 and 2001, treated chickens had similar weight gain as the control group 10 weeks after the first treatment on 7 farms and 12 farms, respectively. The main reason for the very-different weight gain figures seems to be the weather conditions. In 1999, the study site experienced a rainy season with precipitation far above average, whereas in 2000 and 2001 the rainy seasons had precipitations far below average. Based on these findings, routine use of anthelmintics in the study area would only be recommended in wet years when production losses due to helminth infections seem to be pronounced.

In 2001, the study set-up included an assessment of the effect of protein supplementation (soybean) on growth on six farms. Supplemented chickens (treated and non-treated with anthelmintics) had 17% higher weight gain than non-supplemented. Protein supplementation affected neither worm burdens nor faecal egg counts for any of the studied helminths.

The post-mortem examinations showed that Trifén reduced burdens of Ascaridia galli, Heterakis gallinarum, and cestodes (efficacies of 100, 100 and 67%, respectively). Albendazole reduced burdens of H. gallinarum (efficacy of 100%). Efficacies against other helminths were difficult to assess due to low worm burdens. Chickens treated with albendazole had lower Ascaridia and Heterakis faecal egg counts than non-treated chickens.     

Evaluation of Doppler ultrasonography for the measurement of blood flow in young loggerhead sea turtles (Caretta caretta)

The aim of this study was to identify ultrasound accessible blood vessels in the loggerhead sea turtle (Caretta caretta) and describe their Doppler waveform patterns, peak systolic velocity, mean velocity, systolic/diastolic ratio as well as pulsatility and resistive indices. B-mode, colour and pulsed-wave Doppler examinations were performed on 10 turtles. Flow measurements were recorded for the left and right aorta, epigastric and internal iliac arteries, and right hepatic vein. Additionally, the large blood vessels of three dead turtles were injected with latex and dissected for anatomical support. A parabolic flow velocity profile was observed in all arteries. The waveforms of the right and left aortic arteries showed an unusual pattern when compared with mammals. The hepatic vein flow velocity waveform of the loggerhead sea turtle was found to be similar to that in the dog, although the flow velocity in the C-wave was higher than that in the A-wave. The low resistance flow pattern observed suggests that the loggerhead sea turtle's organs require a continuous blood supply.     

Impact on C and N dynamics of simultaneous application of pig slurry and wheat straw, as affected by their initial locations in soil

The joint management of animal manures and plant biomass as straw on agricultural soils may be a viable option for reducing the environmental impacts associated with livestock production and recycling nutrients efficiently. To investigate this option, an incubation in controlled conditions examined how the simultaneous addition of ¹⁵N-labeled pig slurry and ¹³C-labeled wheat straw, either on the soil surface or incorporated into the soil, affected the mineralization of C from the organic materials and the soil N dynamics. Samples from a typic hapludalf were incubated for 95 days at 25°C with eight treatments: unamended soil (S), wheat straw left on the soil surface (Ws), wheat straw incorporated in the soil (Wi), pig slurry on the soil surface (Ps), pig slurry incorporated in the soil (Pi) and three combinations of the two amendments: Pi?+?Ws, Pi?+?Wi, and Ws?+?Ps. Carbon dioxide and ¹³CO₂ emissions and soil N content were measured throughout the incubation. Pig slurry stimulated the decomposition of straw C only when wheat straw and pig slurry were left together on the soil surface. Incorporation of both wheat straw and pig slurry did not modify straw C mineralization when compared to straw incorporation alone but this promoted a higher rate of N immobilization. The results suggest that when pig slurry is used in field under no-till conditions, the best strategy to preserve environmental quality with regard to CO₂ emissions would be to apply pig slurry underneath the crop residues.     

Detection of aluminium tolerance plasmids and microbial diversity in the rhizosphere of plants grown in acidic volcanic soil

The rhizosphere is considered as a hot-spot for gene exchange among bacteria in terrestrial ecosystems. Chilean volcanic soils are characterized by low pH and high concentrations of aluminium (Al) in the soil solution, thus Al tolerance could be important for the survival of microorganisms in these soils; loss of genes encoding for Al tolerance may affect competitiveness particularly in the rhizosphere where competition is strong. The occurrence of Al-tolerance plasmids was investigated in the rhizospheres of pasture and crop plants growing in acidic volcanic soils from southern Chile. Al tolerance plasmids were captured by biparental mating. Two types of Al tolerance plasmids could be distinguished, based on their endonuclease restriction pattern. One plasmid of each group (denoted as pRPA21 and pOPA21) was selected for further studies. The plasmids showed a high stability in presence and absence of Al. Additionally, microbial community composition in the rhizosphere soils was assessed by denaturing gradient gel electrophoresis (DGGE). Sequencing of DGGE bands revealed among others, members of the bacterial phylum Gemmatimonadetes and archaeal phylum Crenarchaeota. The present study shows that the rhizosphere of pasture and crop plants growing in Chilean volcanic soil harbors genetic mobile elements which could play a role in the adaptation of bacterial populations to environmental stressors, such as Al-toxicity.     

Characterization and in vitro digestibility of bovine beta-lactoglobulin glycated with galactooligosaccharides

Galactooligosaccharides (GOS) are well-known prebiotic ingredients which can form the basis of new functional dairy products. In this work, the production and characterization of glycated beta-lactoglobulin (beta-LG) with prebiotic GOS through the Maillard reaction under controlled conditions ( a(w) = 0.44, 40 degrees C for 23 days) have been studied. The extent of glycation of beta-LG was evaluated by formation of furosine which progressively increased with storage for up to 16 days, suggesting that the formation of Amadori compounds prevailed over their degradation. RP-HPLC-UV, SDS-PAGE, and IEF profiles of beta-LG were modified as a consequence of its glycation. MALDI-ToF mass spectra of glycated beta-LG showed an increase of up to approximately 21% in its average molecular mass after storage for 23 days. Moreover, a decrease in unconjugated GOS (one tri-, two tetra-, and one pentasaccharide) was observed by HPAEC-PAD upon glycation. These results were confirmed by ESI MS. The stability of the glycated beta-LG to in vitro simulated gastrointestinal digestion was also described and compared with that of the unglycated protein. The yield of digestion products of glycated beta-LG was lower than that observed for the unglycated protein. The conjugation of prebiotic carbohydrates to stable proteins and peptides could open new routes of research in the study of functional ingredients.     

Targeting carbohydrates: a novel paradigm for fungal control

The tendentious decrease in global arable land and the fast increment in world population will inevitably lead to a critical point. It is therefore imperative to protect crops from pathogen attack. Their deleterious impact on human health is not better, with several invasive infections reaching mortality rates up to 80%. The door is definitely open for biological control, based on molecular interactions between host and pathogen. The remarkable coding capacity of oligosaccharides, far superior to those of nucleotides and amino acids, justifies the emergence of the sugar code as the third life code. The word exoglycome is proposed to represent the oligosaccharide side chains presented at the outer surface of cell membranes, thus excluding the cell wall carbohydrates. The exoglycome plays a fundamental role in cell-cell recognition, in distinction between self from non-self, in the warfare between host and pathogen before infection is established, and in certain diseases such as cancer. Unlike pathogen cell wall carbohydrates, the exoglycome has been neglected as a target for developing effective ways to control disease. Pathogens often induce changes in their cell wall and/or exoglycome to elude and/or circumvent host defences. Identification of such host-induced alterations may prove extremely important for both treatment and diagnosis. Reading the sugar-encoded messages is mainly played by a class of carbohydrate-binding receptors called lectins. The available evidence strongly suggests that a large number of lectins remain to be discovered. Their role in defence should not be underestimated. A high-throughput procedure capable of single-step isolation of novel lections from previously unknown biological samples has recently been developed.     

Conjugates of bovine serum albumin with chitin oligosaccharides prepared through the Maillard reaction

Chitin neoglycoconjugates (BSA-CO) were obtained by the conjugation of bovine serum albumin (BSA) with chitin oligosaccharides (CO) through the Maillard reaction (nonenzymatic glycation). CO produced by acid hydrolysis of chitin were fractionated using an ultrafiltration membrane system (1-3 kDa cutoff). The Maillard reaction was carried out by heating a freeze-dried mixture containing BSA and CO at 60 °C (under 43% relative humidity for 6 and 12 h). BSA-CO were characterized by available amino groups content, intrinsic tryptophan emission spectra, gel electrophoresis, and mass spectrometry. Biological assays included interaction with wheat germ agglutinin (WGA) and with bacterial adhesins of Escherichia coli K88+ and Salmonella choleraesuis. Glycation of BSA was revealed by reduction of available amino groups and fluorescence intensity and also retarded migration through SDS-PAGE. Conjugation of BSA with chitin oligomers appeared to be time dependent and was confirmed by mass spectrometry, by which molecular mass increase for monomers and dimers was observed. Monomers were estimated to contain either one or two glycation sites (at 6 and 12 h of treatment, respectively), with one or two tetrasaccharide units attached. Consequently, dimers showed two or four glycation sites. BSA-CO presented biological recognition by WGA and E. coli K88+ and S. cholerasuis adhesins. The strategy used in this work represents a simple method to obtain glycoconjugates to study applications involving protein-carbohydrate recognition.     

Organoarsenical species contents in fresh and processed seafood products

A study was carried out to determine organic species of arsenic in the main varieties of seafood consumed in the Basque country (Spain). The concentrations of arsenobetaine (AB), dimethylarsinic acid (DMA), monomethylarsonic acid (MMA), arsenocholine (AC), and tetramethylarsonium ion (TMA(+)) in 64 samples corresponding to different food items are presented. The study provides information about a possible distribution pattern of organoarsenical species in seafood products. AB was detected in all of the samples [0.3-104.1 microg g(-1) dry weight (dw)]. DMA was detected in all of the samples except squid and salted cod (0.027-1.757 microg g(-1) dw). MMA was detected only in certain fatty fish (0.004-0.028 microg g(-1) dw) and bivalves (0.031-0.047 microg g(-1) dw). AC was only present in some samples of lean fish (0.014-0.089 microg g(-1) dw), and TMA(+) was detected only in anchovy (0.039-0.169 microg g(-1) dw) and crustaceans (0.044-0.966 microg g(-1) dw).