Evaluating the Suitability of Hazelnut Skin as a Feed Ingredient in the Diet of Dairy Cows

Dietary combination of linseed and hazelnut skin as a sustainable strategy to enrich lamb with health promoting fatty acids

This study investigated the effect of the inclusion of extruded linseed and hazelnut skin on fatty acid (FA) metabolism in finishing lambs. Forty lambs were divided into 4 groups and fed for 60 d with: a conventional cereal-based diet, or the same diet with 8% of extruded linseed, or 15% of hazelnut skin, or 4% of linseed plus 7.5% of hazelnut skin as partial replacement of maize. Dietary treatments did not affect growth performances, carcass traits, and ruminal fermentation. The combined effect of linseed and hazelnut skin enriched the intramuscular fat with health promoting FA. Particularly, increases in α-linolenic acid (3.75-fold), and very long-chain n-3 poly-unsaturated FA (+ 40%) were attributed to the supplementation with linseed, rich in α-linolenic acid. In addition, increases in rumenic (+ 33%), and vaccenic (+ 59%) acids were attributed to hazelnut skin tannins modulating ruminal biohydrogenation and accumulating intermediate metabolites. The simultaneous inclusion of linseed and hazelnut skin can be a profitable strategy for enriching the intramuscular fat of lambs with health promoting FA, without adverse effects on ruminal fermentation and animal performance.

Feeding hazelnut skin to lambs delays lipid oxidation in meat

This study aimed to investigate the effect of dietary hazelnut skin (HNS), a by-product of confectionery industry, on the oxidative stability of lamb meat. Twenty-two finishing lambs were randomly assigned to 2 groups and fed ad libitum for 56 days on different concentrate-based diets: one control and one experimental, in which 150 g/kg of corn was replaced by HNS. After slaughter, the fat-soluble vitamins content and hydrophilic antioxidant capacity were assessed in fresh meat, as well as color, lipid and protein stability over 7 days of shelf-life trial. Dietary HNS increased (P < 0.001) the tocopherols content of meat and reduced (P < 0.001) lipid oxidation during 7 days of refrigerated storage. Meat from lambs fed HNS showed different (P < 0.05) instrumental color parameters. No diet effect (P > 0.05) was observed on the development of metmyoglobin, hydroperoxides, thiol groups, and carbonyl groups. Feeding HNS to lambs improves the oxidative stability of raw meat by delaying lipid oxidation thanks to the antioxidant molecules (tocopherols and phenolic compounds) contained in this by-product.

Valorisation of hazelnut by-products: current applications and future potential

Hazelnut is one of the most widely consumed nuts around the world. Considering the nutritional value of hazelnuts, a wide range of hazelnut-based food products are available in the market such as oil, chocolate, confectionery, etc. Nevertheless, the processing of hazelnuts generates a large number of by-products and waste. The most valuable by-products of the hazelnut industry are shell, skin, and meal. These by-products are rich in bioactive compounds, protein, dietary fibre, mono- and polyunsaturated fatty acids, vitamins, minerals, phytosterols, and squalene. The current utilisation of hazelnut by-products is mostly limited to animal feed supplementation of hazelnut meal and skin and use as a low-value heat source for the shells. However, disposing of these by-products or using them as a low-value heat source or animal feed supplementation results in significant waste of a natural resource rich in nutritional components. Consequently, valorising hazelnut by-products as bioactive ingredients in diverse fields such as food, pharmaceuticals and cosmetics has stimulated interest among scientists, producers, and consumers. This review provides an overview of current scientific knowledge about the main and most valuable hazelnut by-products and their actual valorisation, with a focus on their chemical composition to inspire new applications of these valuable resources and fully exploit their potential.

Hazelnut Skin in Ewes' Diet: Effects on Colostrum Immunoglobulin G and Passive Transfer of Immunity to the Lambs

Passive immunity transfer has a pivotal role in newborn lambs, where the colostrum represents the primary source of immunoglobulins. This study hypothesized that the high content in polyphenolic compounds, mono- and poly-unsaturated fatty acids, and vitamin E of hazelnut skin affects blood and colostrum immunoglobulin G (IgG) concentration and related gamma-glutamyl-transferase (GGT) and lactate dehydrogenase (LDH) levels in sheep and their lambs. In the last 45 days of pregnancy, ewes were divided into a control (CTR) and a hazelnut skin supplemented group (HZN). Blood and colostrum were collected from ewes and lambs before the first suckling, at 24 and 48 h after birth, then IgG concentration, GGT and LDH activity levels were measured. IgG concentration in the colostrum and in lamb's serum were significantly greater in HZN than CTR. No significant difference was detected for ewe's blood. A significant positive correlation was found between IgG and GGT in lambs' serum and colostrum, between IgG and LDH, as well as between GGT and LDH in lambs' serum and colostrum. Our results suggest that hazelnut skin supplementation influences IgG colostrum concentration, with improved immune passive transfer to the suckling lambs. The transfer of maternal derived immune factors is confirmed by the GGT and LDH enzyme activity levels.

Polyphenols for Livestock Feed: Sustainable Perspectives for Animal Husbandry?

There is growing interest in specialized metabolites for fortification strategies in feed and/or as an antioxidant, anti-inflammatory and antimicrobial alternative for the containment of disorders/pathologies that can also badly impact human nutrition. In this context, the improvement of the diet of ruminant species with polyphenols and the influence of these compounds on animal performance, biohydrogenation processes, methanogenesis, and quality and quantity of milk have been extensively investigated through in vitro and in vivo studies. Often conflicting results emerge from a review of the literature of recent years. However, the data suggest pursuing a deepening of the role of phenols and polyphenols in ruminant feeding, paying greater attention to the chemistry of the single compound or to that of the mixture of compounds more commonly used for investigative purposes.

The Sustainability and Development Strategy of a Cattle Feed Bank: A Case Study

One of the Indonesian government’s policies to achieve national beef self-sufficiency is the 1000 beef village program. The program was piloted in many cattle-farming centers involving the operation of a feed bank to supply animal feed to tackle the challenge of feed limitation during the dry season. This study evaluates the sustainability status of an ongoing feed bank program and its development strategy based on the current progress of a feed bank used to serve five groups of farmers. Ninety sustainability attributes were derived based on six dimensions. The attributes were compiled from the primary data collected using a questionnaire. Expert opinions from practitioners were also considered in evaluating the attributes. The feed bank’s sustainability status and development strategy were determined using the multi-dimensional scaling method with the rapid appraisal approach. It was found that the overall sustainability status of the feed bank was less sustainable, with an overall score of 49.55. The individual dimensions of (A) policy and government support, (B) raw material, (C) facilities and infrastructure, (D) feed bank management, (D) human resource management, (E) price, production, and (F) distribution systems posed sustainability scores of 48.48, 60.33, 48.57, 47.89, 48.76, and 44.64, respectively. Among the 90 predefined attributes, 21 were identified as highly sensitive through both the root mean square and expert opinion. Those attributes led to five main recommended development strategies: (1) strengthening the institution, (2) intensifying training, (3) increasing human resources (4) partnership developments, and (5) increasing the role of multi-stakeholders.

Inclusion of Cocoa Bean Shell in the Diet of Dairy Goats: Effects on Milk Production Performance and Milk Fatty Acid Profile

The use of agro-industrial by-products in animal nutrition is a promising strategy to reduce the food-feed competition, the diet cost at farm level and the environmental impact of animal-derived food production. In this study, the suitability of cocoa bean shell (CBS), a by-product of the cocoa industry, as a feed ingredient in the diet of dairy goats was evaluated, with a focus on the related implications on feed intake, milk yield, milk main constituents, and fatty acid (FA) profile of milk fat. Twenty-two Camosciata delle Alpi goats were divided into two balanced groups. All the goats were fed mixed hay ad libitum. The control group (CTRL; n = 11) also received 1.20 kg/head × day of a commercial concentrate, while in the experimental group (CBS; n = 11) 200 g of the CTRL concentrate were replaced by the same amount of pelleted CBS. The total dry matter intake of the goats was reduced by the dietary inclusion of CBS (P ≤ 0.01). The milk yield, as well as the milk fat, protein, and casein contents and yields were unaffected by the treatment. Milk from the CBS-fed goats showed decreased urea content when compared to the CTRL group (P ≤ 0.001). Milk from the CBS group of goats also showed increased concentrations of total branched-chain FA (both iso and anteiso forms; P ≤ 0.001) and total monounsaturated FA (P ≤ 0.05), as well as a decreased ∑ n6/∑ n3 FA ratio (P ≤ 0.05). De novo saturated FA, total polyunsaturated FA, total conjugated linoleic acids, and the majority of ruminal biohydrogenation intermediates remained unaffected by the dietary treatment. These results suggest that CBS can be strategically used as an alternative non-conventional raw material in diets intended for lactating goats, with no detrimental effects on their milk production performance. The use of CBS in goat nutrition may be hindered by the presence of theobromine, a toxic alkaloid. Special attention is needed by nutritionists to avoid exceeding the theobromine limits imposed by the current legislation. Detheobromination treatments are also suggested in literature to prevent toxic phenomena.

Effect of Dietary Hazelnut Peels on the Contents of Fatty Acids, Cholesterol, Tocopherols, and on the Shelf-Life of Ripened Ewe Cheese

Hazelnut peel (HNP), a by-product from the chocolate industry, is considered to be a suitable ingredient to be included in the diet of ruminants. This study aimed to evaluate the effect of feeding dairy ewes with a diet containing HNP on ripened cheese quality, including fatty acid (FA) profile, cholesterol, and tocopherol content, as well as stability during storage under commercial conditions. In total, 10 experimental cheeses were produced with bulk milk obtained from ewes fed a commercial concentrate (C group; n = 5) or a concentrate containing 36% HNP in dry matter (HNP group; n = 5). After 40 days of aging, each cheese was sub-sampled into three slices: one was analyzed immediately (C0 and HNP0), and the other two were refrigerated and analyzed after seven days (C7 and HNP7) and 14 days (C14 and HNP14), respectively. Compared to C, HNP cheese had more than twice as many tocopherols and mono-unsaturated FA and respectively 38% and 24% less of cholesterol and saturated FA. Tocopherols and cholesterol levels remained rather stable up to 14 days of storage regardless of the experimental group, suggesting no cholesterol oxidation. Therefore, the inclusion of HNP in ewe diets could be a valid resource to produce cheese with a healthier lipid profile and higher tocopherols content.