Effect of starch gelatinisation on nutrient digestibility and plasma metabolites in pigeons

Feed manufacturing exerts physical and chemical changes in ingredients, including the gelatinisation of starch. Studies on the effect of the degree of starch gelatinisation on nutrient digestibility, metabolism and subsequent performance show inconsistent results, and no data are available in pigeons. In a cross‐over trial, fourteen adult pigeons were randomly divided into two groups, in which two extruded pellet diets were tested. Both the diets were similar in ingredient composition and nutrient content, but differed in extrusion conditions, resulting in a different degree of starch gelatinisation: pellets with high gelatinisation degree (HG; 73.6% gelatinisation) and low gelatinisation degree (LG; 53.1% gelatinisation). After a 14‐day adaptation period, all excreta were gathered per bird during a 5‐day collection period. Coefficients of apparent digestibility of dry matter (DM), crude protein (CP), ether extract (EE), crude fibre (CF), crude ash (CA) and nitrogen free extract (NFE) as well as apparent nitrogen retention were calculated from proximate analyses of feed and excreta. Further, excreta consistency was subjectively scored. Blood samples were taken at the end of each period and plasma samples were analysed for glucose, fructosamine and triglycerides. Feed intake and body weight changes were recorded weekly. The apparent digestibility coefficients (ADCs) of DM, OM, CP, EE, CA and NFE were significantly higher in the LG group (p ≤ 0.05). The ADC of crude fibre was numerically higher in the LG group but not significant, and no significant differences were found in starch digestibility. Excreta consistency score tended to be higher in the LG diet group. Neither plasma glucose nor plasma fructosamine values were significantly different between the two test diets. The results of this study show that lower degree of starch gelatinisation in extruded diets can enhance digestibility in pigeons.     

Effects of Culinary Methods on Nutritional Characteristics of the Edible Shellfish Noah’s Ark (Arca noae L., 1758) from Tunisian Coasts

Bivalves are known for their high nutritional value and are considered a healthy food for human consumption. The effect of different cooking methods (steaming, boiling, grilling, and frying) on proximate and fatty acid composition of Arca noae (Bivalvia: Linnaeus 1758) were determined. The comparison of raw and cooked Ark shell showed that the cooking had considerable effects on the nutritional quality of this species. Significant changes in moisture (%), protein (mg/g of flesh), total lipid (mg/g of flesh), and fatty acid composition (mg/g dry weight) were observed after cooking as compared to fresh Ark shell (p < 0.05). However, the analysis of malondialdehyde (MDA) and peroxide value (PV) showed that all cooking treatments led to lipid oxidation. Steaming, boiling, and grilling were found to be a suitable and healthier cooking processes for A. noae, since they conserve the amount of n-3 PUFA better as compared to frying.     

Fish meal replaced by hydrolysed soybean meal in diets increases growth and improves the antioxidant defense system of silver catfish (Rhamdia quelen)

One of the current challenges of global fish farming is developing plant‐based proteins as a feasible substitute for fishmeal in the formulation of aquafeeds. Substitution levels of fishmeal with hydrolyzed soybean meal (HSM) in diets for silver catfish (Rhamdia quelen) were evaluated for growth, protein metabolism and antioxidant activity. The experiment was carried out in a recirculation system of 20 tanks of 250 L. A total of 300 silver catfish juveniles were used to compose five treatments and four replicates per treatment. Levels of soybean hydrolysate (0%, 5%, 10%, 15% and 20%) were tested in diets (39% protein and 3,500 Kcal) for 60 days. Silver catfish growth was higher at all inclusion levels of HSM when compared to the control diet. No change was shown for body protein deposition. The production of nitrogenous compounds in the liver and muscle was also unaffected by any of the diets. The diet containing 20% HSM promoted an increase in the amounts of non‐protein thiols in the gills and brain. The HSM substitution levels of up to 20% of fishmeal in the diet increases growth and contributes to silver catfish antioxidant activity.     

Haematopoiesis in the head kidney of common carp (<Emphasis Type="Italic">Cyprinus carpio</Emphasis> L.): a morphological study

The morphogenesis of head kidney haematopoietic cells in common carp has been shown to be very similar to that of higher vertebrates. The erythropoietic series consisted of the erythroblasts (basophilic, polychromatic and orthochromic), young erythrocyte and erythrocyte. The morphological changes that occur during maturation process are reduction in size and further increase at mature stage, gradual chromatin condensation and the increase in haemoglobin content. Maturation stages of neutrophils and basophils encompassed the young progranulocyte, progranulocyte and metagranulocyte. The early blast cells, basophilic lineage and lymphocytes were regularly present in kidney. In the monocytoid series in kidneys, promonocytes and mature monocytes were observed. Precursor stages of the eosinophile and thrombocyte were not discernible (although mature cells were observed). Lymphoid cells were the most abundant, followed by granuloid, thrombocyte, erythroid, blast and monocytoid cells. The neutrophilic progranulocyte was the most frequent granuloid cell. The lymphocyte was the most frequent cell in the kidney and the most numerous of the lymphoid lineage.     

Correction to: A prioritised inventory of crop wild relatives and wild harvested plants of Tunisia

Genetic Resources and Crop Evolution -