Cocoa by-product inclusion in dairy sheep diet: effect on sensory, volatile and antioxidant properties of cheese.

The possibility of inclusion of agro-industrial by-products in the diet of small ruminants represents both an economical and an environmental strategy for reducing waste management by industries and the cost of feeding as well as the impact of livestock farming. Large amounts of wastes from the cocoa industry are annually produced with a considerable part represented by cocoa bean shells, considered a suitable ingredient to be included in the diet of ruminants within the limits established by European legislation. The aim of this study was to assess the effect of including cocoa bean shells in the diet of dairy sheep on the sensory, volatile, and antioxidant properties of cheese. To this purpose, 20 Comisana lactating ewes were randomly assigned to 2 experimental groups: control (CTRL) and cocoa bean shells (CBS), and received alfalfa hay ad libitum and 800g of conventional (CTRL) or experimental (CBS) concentrate containing 11.7% CBS to partially replace corn and barley of the CTRL concentrate. Bulk milk collected from each group was used to produce a total of 15 cheeses per group, obtained in 5 different days of cheese-making (3 cheeses a day per group). After 60 d of aging, each cheese of each experimental group was sampled for the analyses. The results on chemical composition revealed a greater monounsaturated fatty acids content and an increase in the nutritional indices suggesting a favorable role of cocoa bean shells dietary inclusion on the nutritive value of the cheese. The cheese sensory profile was affected by the cocoa bean shells inclusion, with more pronounced appearance, odor, aroma, and taste attributes in the product. The volatile profile showed only a few significant differences, mainly related to the cheese ripening process, and no differences were found in α-tocopherol contents in cheese fat between the 2 groups. Therefore, the coca bean shells inclusion in the diet of dairy sheep allowed to obtain a good quality cheese, without altering the characteristics associated with the typical profiles of sheep cheese. Furthermore, the use of this by-product could contribute to decrease feed costs and waste management, representing a good practice for increasing the sustainability of dairy products.

Graduate Student Literature Review: History, technologies of production, and characteristics of ricotta cheese.

This review focused on the historical, technological, and analytical characteristics of ricotta cheese available in the literature. Ricotta cheese is a typical dairy product that originated from Italy, used in the preparation of several traditional dishes, both sweet and salted. The available studies pertaining to ricotta cheese revealed a considerable biodiversity in the production with a large number of varieties produced, whose production varies according to the local uses and customs. The review shows the main chemical and microbial characteristics of the product and also the several parameters that affect the mechanism of the production process and the final characteristics of the product, including the raw materials, the processing methods, the season, the animals' diet, the animals' species, and breeds. Ricotta production can be artisanal or industrial, with differences in the making process. New trends in ricotta cheese production have been developed, with particular attention to the functional effect on human health and the novel technologies applied to extend the shelf-life of the products. Currently, it is not easy to find these new developments in the market, probably related to the cost of production, which is not always bearable by the farms. However, despite the large classification reported and the great interest by the cheese industry, just a few numbers of studies were found for artisanal ricotta productions, which still need to be characterized and studied.

Feeding tannins to dairy cows in different seasons improves the oxidative status of blood plasma and the antioxidant capacity of cheese.

The aim of the present study was to assess the dietary supplementation of tannins to grazing dairy cows in 2 seasons characterized by a good quality pasture (spring) or a poor-quality pasture (summer). The effects of dietary tannins were assessed on plasma antioxidant status and cytokines profile and on the antioxidant properties of cheese and cheese in vitro digestates. Fourteen lactating dairy cows were divided into 2 homogeneous groups (n = 7): a control group (CON), and an experimental group (TAN) receiving 150 g/head per day of tannins supplementation. The experiment was performed twice, in spring and in summer. The animals were free to graze on spontaneous pasture (spring) or on dry stubble (summer). Blood was sampled at the beginning (d 0), at the midpoint (d 11), and at the end (d 22) of the trial. Individual cheese was produced before the beginning (d -1) and at the end (d 22) of the trial from the milk collected from each cow. On blood plasma, the reactive oxygen metabolites (ROM), biological antioxidant potential (BAP), nonesterified fatty acids quantification, and cytokines profile in terms of IL-10, IL-8, IL-1ß, and IFN-γ were determined. Data on ROM demonstrated that tannins supplementation lowered oxidative stress both in spring and in summer. Accordingly, TAN diet increased BAP levels compared with the CON during summer trial. Thus, feeding tannins resulted in lower ratio between ROM and BAP (oxidative stress index) in both spring and summer. Cytokines' profile showed lower IL-1ß values in TAN group at d 22 during spring season, with a concomitant higher IL-10 level, during summer season. Moreover, TAN group had a lower level of IFN-γ in plasma than CON group, both in spring and in summer. On cheese samples, the in vitro digestion was performed and on cheese and cheese digestates (gastric and intestinal digestate) the free radical scavenging antioxidant activity was evaluated. The intestinal digestate fraction registered the highest antioxidant activity compared with cheese and gastric digestate, in both spring and summer seasons. Furthermore, an improvement of the antioxidant property of cheese and cheese digestates was found. Present data demonstrated that tannins supplementation contributed to reduce the oxidative stress of lactating dairy cows and showed an increase of anti-inflammatory cytokines ratio.

Effects of forage quantity and access-time restriction on feeding behaviour, feed efficiency, nutritional status, and dairy performance of dairy cows fed indoors.

Optimising feed is a key challenge for dairy livestock systems, as forage stock shortages are increasingly frequent and feed is the biggest operating cost. The aim of this experiment was to evaluate the effects of reducing forage quantity and access time on dairy performance and animal nutritional status during indoor feeding. Twenty-seven Montbéliarde and Holstein cows were randomly allocated to three groups of nine cows balanced by breed, parity, days in milk, and milk yield. The three groups were given 3.9 kg DM/day of second-cut hay and 4.5 kg/day of concentrate and either i) ad libitum access to first-cut hay (Ad Libitum group; AL), ii) 10.5 kg/day of first-cut hay (Quantity-restricted group; QR), or iii) 10.5 kg/day of first-cut hay but with access time restricted to only 2 h in the morning and 2 h in the afternoon (Quantity-and-Time-restricted group; QTR). Milk yield, composition and coagulation properties, cow nutritional status (weight, body condition score, blood metabolites) and cow activities were recorded. The AL group ingested 10 % more feed than the QR group and 16 % more feed than the QTR group. Organic matter digestibility was lower in the AL group than in the QR and QTR groups whereas feed efficiency did not differ. Milk yield was not significantly different among the three groups. Compared to the QR and QTR groups, the AL group had significantly higher milk fat (35.9 vs 32.9 and 32.8 g/kg of milk) and milk protein content (29.5 vs 27.7 and 28.5 g/kg of milk). QR and QTR cows mobilised their body fat, resulting in a lower final body condition score, and tended to have a lower blood non-esterified fatty acid concentration than the AL group. QTR cows showed greater body fat mobilisation, but their final corrected BW was not different from AL cows. Access-time restriction did not impact fat and protein content but led to decreased casein, lactose contents and casein-to-whey protein ratio. The forage savings achieved through this feed management practice could prove economically substantial when forage prices increase. This practice can be of interest in grassland systems to overcome certain climatic hazards without having to resort to purchases or to increase the farm's forage autonomy.

Effect of dietary tannin supplementation on cow milk quality in two different grazing seasons.

Extensive farming systems are characterized by seasons with different diet quality along the year, as pasture availability is strictly depending on climatic conditions. A number of problems for cattle may occur in each season. Tannins are natural polyphenolic compounds that can be integrated in cows' diet to overcome these seasonal problems, but little is known about their effect on milk quality according to the season. This study was designed to assess the effects of 150 g/head × day of tannin extract supplementation on proximate composition, urea, colour, cheesemaking aptitude, antioxidant capacity, and fatty acid (FA) profile of cow milk, measured during the wet season (WS) and the dry season (DS) of Mediterranean climate. In WS, dietary tannins had marginal effect on milk quality. Conversely, in DS, the milk from cows eating tannins showed 10% lower urea and slight improvement in antioxidant capacity, measured with FRAP and TEAC assays. Also, tannin extract supplementation in DS reduced branched-chain FA concentration, C18:1 t10 to C18:1 t11 ratio and rumenic to linoleic acid ratio. Tannins effect on rumen metabolism was enhanced in the season in which green herbage was not available, probably because of the low protein content, and high acid detergent fibre and lignin contents in diet. Thus, the integration of tannin in the diet should be adapted to the season. This could have practical implications for a more conscious use of tannin-rich extracts, and other tannin sources such as agro-industrial by-products and forages.

Cheese quality from cows given a tannin extract in 2 different grazing seasons.

The aim of the present study was to compare the effect of dietary tannins on cow cheese quality in 2 different grazing seasons in the Mediterranean. Two experiments were performed on 14 dairy cows reared in an extensive system. The first experiment took place in the wet season (WS), and the second experiment took place in the dry season (DS). In the WS and DS experiments, cows freely grazed green pasture or dry stubbles, respectively, and the diet was supplemented with pelleted concentrate and hay. In both experiments, the cows were divided into 2 balanced groups: a control group and a group (TAN) receiving 150 g of tannin extract/head per day. After 23 d of dietary treatment, individual milk was collected, processed into individual cheeses, and aged 25 d. Milk was analyzed for chemical composition, color parameters, and cheesemaking aptitude (laboratory cheese yield and milk coagulation properties). Cheese was analyzed for chemical composition, proteolysis, color parameters, rheological parameters, fatty acid profile, and odor-active volatile compounds. Data from the WS and DS experiments were statistically analyzed separately with an analysis of covariance model. In the WS experiment, dietary tannin supplementation had no effect on milk and cheese parameters except for a reduced concentration of 2-heptanone in cheese. In the DS experiment, TAN milk showed lower urea N, and TAN cheese had lower C18:1 trans-10 concentration and n-6:n-3 polyunsaturated fatty acid ratio compared with the control group. These differences are likely due to the effect of tannins on rumen N metabolism and fatty acid biohydrogenation. Dietary tannins may differently affect the quality of cheese from Mediterranean grazing cows according to the grazing season. Indeed, tannin bioactivity on rumen metabolism seems to be enhanced during the dry season, when diet is low in protein and rich in acid detergent fiber and lignin. The supplementation dose used in this study (1% of estimated dry matter intake) had no detrimental effects on cheese yield or cheesemaking parameters. Also, it is unlikely that sensorial characteristics would be affected by this kind of dietary tannin supplementation.

Inclusion of cocoa by-product in the diet of dairy sheep: Effect on the fatty acid profile of ruminal content and on the composition of milk and cheese.

In this study, we hypothesized that dietary cocoa bean shell (CBS) as a partial replacer of human edible cereal grains in the diet of lactating ewes may affect performance and milk and cheese composition. Twenty Comisana lactating ewes allotted into control (CTRL; n = 10) or cocoa (CBS; n = 10) group received alfalfa hay ad libitum and 800 g of conventional (CTRL) or experimental (CBS) concentrate containing 11.7% CBS to partially replace corn and barley of the CTRL concentrate. Milk yield and composition did not differ between groups, and only urea concentration was lower in CBS milk. Dietary CBS increased cheese fat and reduced protein percentage in CBS group. Fatty acid composition of rumen content partially reflected that of the ingested diet, with total saturated fatty acids (SFA), total monounsaturated fatty acids (MUFA), 16:0, 18:0 and 18:1c9 greater in the CBS group. Moreover, all the identified trans- and cis-18:1 isomers were greater in CBS rumen content. Milk and cheese showed a similar fatty acid composition. Total MUFAs were greater in milk and cheese of CBS, mainly due to the proportion of 18:1c9, and conversely, total polyunsaturated fatty acids (PUFA), PUFAn-6 and PUFAn-6-to-PUFAn-3 ratio was greater in CTRL group. Concluding, the inclusion of CBS in the diet of lactating ewes within the limit imposed by the current legislation did not cause detrimental effects on animal performance and milk composition. Interestingly, dietary CBS reduced milk urea concentration probably due to the phenols contained in CBS concentrate. However, our results support that biohydrogenation was weakly impaired by dietary CBS. Finally, CBS negatively affected cheese nutritional characteristics due to lower protein and greater fat content, but improved fat health indexes in milk and cheese.

Effect of different dietary tannin extracts on lamb growth performances and meat oxidative stability: comparison between mimosa, chestnut and tara.

Little information is available on the effects of different sources of tannins on ruminant product quality. Nowadays several tannin-rich extracts, produced from different plants, are available and contain tannins belonging to different chemical groups, but most of these have not been used so far as feed supplements. The present study aimed at comparing the effects of feeding three tannin extracts (one containing condensed tannins and two containing hydrolysable tannins) to lambs on growth performances and meat oxidative stability. Comisana male lambs were divided into four groups (n=9 each) and were fed for 75 days: a concentrate-based diet (CON), or CON supplemented with 4% tannin extracts from either mimosa ( MI; Acacia mearnsii, De Wild; condensed tannins), chestnut (CH; Castanea sativa, Mill; hydrolysable ellagitannins) or tara (TA; Cesalpinia spinosa, (Molina) Kuntze; hydrolysable gallotannins). Only CH reduced growth rate, final weight, carcass weight and feed intake (P0.05). The TA diet increased (P<0.001) the concentration of γ-tocopherol in muscle and tended to increase that of α-tocopherol (P=0.058). Oxidative stability of raw and cooked meat, or of meat homogenates incubated with pro-oxidants, was not affected by the extracts. These results, compared with those reported in the literature, highlight that some effects of tannins cannot be easily generalized, but may strictly depend on their specific characteristics and on conditions inherent to the basal diet and the metabolic status of the animals.

Vitamin E is the major contributor to the antioxidant capacity in lambs fed whole dried citrus pulp.

The aim of this study was to investigate the effect of dietary whole dried citrus pulp (DCP) on the antioxidant status of lamb tissues. In total, 17 lambs were divided into two groups and fed for 56 days: a barley-based concentrate diet (CON - eight animals), or a concentrate-based diet including 35% DCP to partially replace barley (CIT - nine animals). The CIT diet contained a double concentration of phenolic compounds than the CON diet (7.9 v. 4.0 g/kg dry matter (DM), respectively), but had no effect (P>0.05) on the overall antioxidant capacity of the hydrophilic fraction of blood plasma, liver and muscle. The CIT diet contained clearly more α-tocopherol than the CON diet (45.7 v. 10.3 mg/kg DM), which could explain the higher concentration of α-tocopherol in liver, plasma and muscle (P<0.05). The dietary treatment had no effect on the extent of lipid peroxidation, measured as thiobarbituric acid and reactive substances assay (TBARS values) in the faeces, small intestine, liver, plasma and muscle. Nevertheless, when muscle homogenates were incubated in the presence of Fe3+/ascorbate to induce lipid peroxidation, the muscle from lambs fed DCP displayed lower TBARS values (P<0.01), which negatively correlated with the concentration of α-tocopherol in muscle. These results showed that feeding whole DCP to ruminants increases the antioxidant status of muscle through an increase in the deposition of α-tocopherol.

Effects of recombinant protein misfolding and aggregation on bacterial membranes.

The expression of recombinant proteins is known to induce a metabolic rearrangement in the host cell. We used aggregation-sensitive model systems to study the effects elicited in Escherichia coli cells by the aggregation of recombinant glutathione-S-transferase and its fusion with the green fluorescent protein that, according to the expression conditions, accumulate intracellularly as soluble protein, or soluble and insoluble aggregates. We show that the folding state of the recombinant protein and the complexity of the intracellular aggregates critically affect the cell response. Specifically, protein misfolding and aggregation induce changes in specific host proteins involved in lipid metabolism and oxidative stress, a reduction in the membrane permeability, as well as a rearrangement of its lipid composition. The temporal evolution of the host cell response and that of the aggregation process pointed out that the misfolded protein and soluble aggregates are responsible for the membrane modifications and the changes in the host protein levels. Interestingly, native recombinant protein and large insoluble aggregates do not seem to activate stress markers and membrane rearrangements.

Protein-protein and protein-ligand interactions studied by electrospray-ionization mass spectrometry.

Preservation of non-covalent interactions in biopolymer mass spectrometry offers new approaches to binding analysis. Recent work from our laboratory is reviewed here and discussed with reference to recent literature in the field. Three issues are considered in particular: hydrophobically stabilized complexes, pH-dependent transitions, and linked protein-ligand and protein-protein binding equilibria.