Effect of dietary supplementation with algae extracts on growth performance and caecal microbiota of broiler chickens.

1. The objective of this study was to test the dose response of dietary supplementation with algae extracts rich in marine-sulphated polysaccharides (MSP1 and MSP2) on the growing performance, body composition at slaughter and caecal microbiota of broiler chickens.2. Male broiler Ross 308 chicks 1-d-old were distributed into eight groups, a control group (unsupplemented), four groups supplemented with increasing doses of algae extract MSP1 (40, 81, 121 and 162 g/ton feed) and three groups supplemented with increasing doses of algae extract MSP2 (40, 81 and 162 g/ton feed). Each group comprised six pens of 56 chickens.3. All chickens were reared under challenging conditions, i.e. high rearing density of 42 kg/m2, fed growing and finishing diets containing, palm oil, rye and high levels of wheat and subjected to short daily fasting periods. The growth performance was recorded during rearing. At 10, 22 and 31 d of age, 12 chickens per group were euthanised to collect the caecal contents and determine microbiota composition and short-chain fatty acid levels. At d 35, the quality of litter and the condition of feathers, footpads and tarsals were scored. At d 36, 7 chickens per pen were slaughtered under commercial conditions to determine carcass composition and breast meat quality (ultimate pH and colour).4. Algal extract MSP1 increased the weight of the caeca and butyrate concentration in the caeca at d 22 (p ≤ 0.05). It increased the ultimate pH of breast fillet measured after slaughter at d 36 (p ≤ 0.05). Moreover, the group receiving 162 g/t MSP1 had a more diverse microbiota at d22. However, algal extract MSP2 had negligible effect on the different measured parameters.

Plant and soil intake by organic broilers reared in tree- or grass-covered plots as determined by means of n-alkanes and of acid-insoluble ash.

Free-range birds such as organic broilers may ingest soil and plants during exploration. The estimation of such intakes is of great interest to quantify possible nutritional supplies and also to evaluate the risk of exposure to parasites or to environmental contaminants. Marker-based techniques are now available and would allow to quantify plant and, especially, soil intake in free-range birds, and this quantification was the aim of this study. Methodologically, the proportion of plants in diet intake was determined first using a method based on n-alkanes. Subsequently, the fraction of soil in the total intake was estimated with a second marker, acid-insoluble ash. This approach was carried out to estimate ingested amounts of plants and soil for five successive flocks of organic broilers, exploring grass-covered yards or those under trees, at two time points for each yard: 51 and 64 days of age. Each factor combination (yard type×period=flock number×age) was repeated on two different yards of 750 broilers each. The birds' plant intake varied widely, especially on grass-covered yards. The proportion of plant intake was significantly higher on grass-covered plots than under trees and was also affected, but to a lesser extent, by age or flock number. The ingestion of plants would generally not exceed 11 g of DM daily, except two extreme outliers of nearly 30 g. The daily plant intake under trees tended to be lower and never exceeded 7 g of DM. The amount of ingested plants increased significantly for spring flocks. It increased slightly but significantly with age. The proportion of ingested soil was significantly higher under trees than on grass-covered yards. Dry soil intake was generally low with not more than 3 g per day. Only in adverse conditions - that is, older birds exploring yards under trees in winter - soil intake reached the extreme value of nearly 5 g. Broilers on yards under trees ingested significantly more soil than on grass-covered yards with least square means of, respectively, 2.1 and 1.1 g dry soil per day. These quantifications would allow us to evaluate the impact of plant and soil intake in the management of free-range broilers, especially for the management in organic farming systems. Nevertheless, under the two rearing conditions tested in the current study, the quite low proportions of soil intakes would represent a low risk for the safety of the produced food, unless the birds explore yards on heavily contaminated soil.

Survival of functional pancreatic acinar tissue in circumfusion organ culture enhanced by chemically defined medium with hydrocortisone.

Pancreatic explants from perinatal or 1-week-old rat circumfusion organ cultured with an insulin-free variant of Trowell's Medium T8 survive functionally, as judged from tissue amylase content, for about 3 days. When hydrocortisone 21-sodium succinate, 1.0 mg/liter, is added to the chemically defined medium, high levels of anylase persist for longer periods. Explants from 7-day-old animals, circumfusion cultured with hydrocortisone-supplemented medium, maintain tissue amylase levels equal to or greater than those of uncultured control pancreas for at least 5 days of culture, and over this period they release amylase into culture medium at a stable rate. Methods for maintaining functional pancreatic acinar tissue in culture provide a new biological model for in vitro analysis of the early defects of potential chemical carcinogens on this target organ.

Evaluation of a red cell agglutination test for detection of Australia antigen (HG Ag).

An investigational red cell agglutination (RCA) test was evaluated for sensitivity in detecting and titering hepatitis B antigen (HB Ag) in comparison with two counterelectrophoresis (CEP) systems and a solid-phase radioimmunoassay (RIA). The RCA procedure was found to be significantly more sensitive than the CEP methods and compares favorably in sensitivity with the solid-phase RIA, detecting even lower concentrations of the HB Ag. Since the RCA test can be completed in 2 to 3 h and requires relatively inexpensive equipment, it offers a highly sensitive and rapid procedure suitable for use in blood banks to screen donors or detect low levels of antigen in serum of patients.