Paola Lupi

The aim of the study was to evaluate milk fatty acid (FA) profile, animal performance, and rumen microbial population in response to diets containing soybean oil supplemented or not with chestnut and quebracho tannins in dairy ewes. Eighteen Comisana ewes at 122±6 d in milking were allotted into 3 experimental groups. Diets were characterized by chopped grass hay administered ad libitum and by 800 g/head and day of 3 experimental concentrates containing 84.5 g of soybean oil/kg of dry matter (DM) and 52.8 g/kg of DM of bentonite (control diet), chestnut tannin extract (CHT diet), or quebracho tannin extract (QUE diet). The trial lasted 4 wk. Milk yield was recorded daily, and milk composition and blood parameters were analyzed weekly. At the end of the experiment, samples of rumen fluid were collected to analyze pH, volatile fatty acid profile, and the relative proportions of Butyrivibrio fibrisolvens and Butyrivibrio proteoclasticus in the rumen microbial population. Hepatic functionality, milk yield, and gross composition were not affected by tannin extracts, whereas milk FA composition was characterized by significant changes in the concentration of linoleic acid (CHT +2.77% and QUE +9.23%), vaccenic acid (CHT +7.07% and QUE +13.88%), rumenic acid (CHT -1.88% and QUE +24.24%), stearic acid (CHT + 8.71% and QUE -11.45%), and saturated fatty acids (CHT -0.47% and QUE -3.38%). These differences were probably due to the ability of condensed versus hydrolyzable tannins to interfere with rumen microbial metabolism, as indirectly confirmed by changes in the relative proportions of B. fibrisolvens and B. proteoclasticus populations and by changes in the molar proportions of volatile fatty acids. The effect of the CHT diet on the milk FA profile and microbial species considered in this trial was intermediate between that of QUE and the control diet, suggesting a differential effect of condensed and hydrolyzable tannins on rumen microbes. Compared with control animals, the presence of B. fibrisolvens increased about 3 times in ewes fed CHT and about 5 times in animals fed QUE. In contrast, the abundance of B. proteoclasticus decreased about 5- and 15-fold in rumen liquor of ewes fed CHT and QUE diets, respectively. The use of soybean oil and a practical dose of QUE or CHT extract in the diet of dairy ewes can be an efficient strategy to improve the nutritional quality of milk.

The aim of the study was to evaluate the effect on the final product quality of certain innovative stunning/killing methods for sea bass as substitutes for the most common methods used by European farmers. The changes in tissue stress/quality parameters were monitored from the first hours after death and during the shelf life of the fish. Two trials were conducted in July and November on n. 231 sea bass stunned/killed by ice-water slurry, by single gas or mixture of gases in ice-water and by single- or two-stage electrical stunning/killing methods. Behavioural responses, stun/death time, rigor index, muscular and ocular pH, lactic acid, ATP and catabolites at death and within the 24 h after death were determined. In the November trial, the sensorial evaluation, rigor index, IMP, inosine, hypoxanthine, and K₁ values were also evaluated during refrigerated storage until spoilage. The stunning/killing in ice-water appeared to induce low effects on the analysed parameters and preserve a good product quality as indicated by the highest pH and ATP values at death, the delayed full rigor onset and the 1 day longer shelf life (14 days) in comparison with the single- or two-stage electrical stunning/killing. The gas mixture addition provided a 40 % shortening of the time to obtain stunning/killing and 14 days of shelf life. The actual level of quality loss with the different killing conditions and the actual impact of a significant shortage of rigor mortis onset and pH drop on the possible pre-rigor filleting remain to be studied in depth.

Physico-chemical traits of raw and cooked fillets of rainbow trout (Oncorhynchus mykiss) from different strains and farms

Effect of rearing system on body traits and fillet quality of meagre (Argyrosomus regius, Asso 1801) chilled for a short time

Fish samplings were carried out monthly from spring to autumn during 2008, on the Lamone river and the Campigno stream by an electrofishing, in order to verify the presence of fish populations and the most common species represented. Barb, Barbus plebejus, Blageon, Leuciscus muticellus, Chub, Leuciscus cephalus, South European Nase, Chondrostoma genei were identified. A small population of Brown trout, Salmo trutta fario was also recognized. Barb is the most represented species in all the sites. The samplings highlight that Lamone river presented conditions suitable to fully guarantee the life of the fish populations.

The haematic pattern of Maremmana cattle of Grosseto area was studied, to investigate the causes of the often found low reproductive efficiency. The provided data are related to some haematic parameters measured in different seasons in Maremmana cattle fed three different diets: Standard diet (pasture + hay in critical periods): diet A; standard diet integrated with mineral salts: diet B; standard diet + mineral salts + concentrated mixed feed): diet C. The season influenced all parameters, while no difference was found among diets. Among the mineral elements, phosphorous showed values always above norm.

To evaluate the influence of fattening on morphological, nutritional and safety characteristics, two lots of bluefin tuna were sampled before (November: 2 C, 4 ?) and after 5 months of fattening (April: 5 C, 5 ?). The specimens, after death, were refrigerated and analysed at different times over the period of a week for morphological and flesh physico-chemical parameters in six muscle sites. Tuna sampled in April had greater body weight (44.04 vs 36.41kg), trunk length (52.21 vs 48.22cm) and minimum and maximum circumferences (13.74 vs 12.77 and 94.90 vs 89.10cm). No differences in other linear measures or body components were found. Fattening did not influence flesh colour or total lipid content, producing small differences in its chemical composition: greater C18:0, C18:1n9 and PUFAn6 percentages; higher putrescine and histamine (0.489 vs 0.335 and 0.666 vs 0.370mg/kg) but lower spermine and spermidine (10.598 vs 17.387 and 2.420 vs 3.928mg/kg) levels. Large differences in physico-chemical parameters were found between muscle sites and a significant interaction between sampling date and muscle site indicated non homogeneous changes in chemical composition of dorsal, ventral and red muscle after fattening. Sex only influenced fat content in viscera (C 12.84 vs ? 9.84%).

Welfare and quality of farmed trout fed high plant protein diets. 2 innovative killing method effect on stress and quality indicators

Physical and organoleptic traits in commercial size bluefin tuna (Thunnus thynnus) reared in floating cage