Ingested versus inhaled limonene in sheep: A pilot study to explore potential different transfer to the mammary gland and effects on milk and Caciotta cheese aroma

Concentration is a key determinant in the overall positive impact of terpenes on milk and cheese aroma; additionally, route of intake may affect the achievable concentrations of dietary terpenes in milk and cheese. In this study, we explored the possibility that the amount of the monoterpene limonene transferred to sheep milk and its corresponding cheese could differ depending on the route of intake and that the aroma profile of these products could also differ. To this aim, 12 lactating dairy ewes were repeatedly exposed to limonene by the oral or respiratory route during a 48-h test period, according to a 3 × 3 Latin square experimental design. Limonene content was measured in individual and bulk milk samples, in 1-d-old and 15-d-old Caciotta cheese obtained from that milk, in the related whey and curd, and in the air inhaled by the ewes in the respiratory treatment group (to obtain an estimate of the dose actually supplied by this route). Bulk milk and fresh (1-d-old) cheese underwent sensory analysis by ortho-olfactory evaluation. Both intake routes demonstrated transfer of limonene to milk, but the respiratory route transferred limonene with greater efficiency than the oral route. Moreover, according to the protocol used in this study, a short period of respiratory exposure induced a slightly higher limonene content in milk compared with oral exposure. As to the fate of limonene during cheesemaking, an important part of it was lost into the whey, perhaps through volatilization. The differences between milk and cheese tended to dissipate in curd and fresh cheese and disappeared completely after 15 d of ripening. Finally, it was possible to distinguish between the 2 routes of limonene intake using sensory analysis, even though no direct relationship was identified between the different aroma profiles of milks and cheeses from the oral and respiratory groups and their respective limonene contents. Overall, our results expand current knowledge on the biological pathways of terpene transfer from feed to sheep milk and cheese, as well as on the role played by terpenes in the formation of aroma in these products. Our observations may contribute to future development of strategies for external control and better standardization of the presence of odor compounds in milk and cheese from dairy ruminants.

The environmental impacts of citrus residue management in China: A case study in The Three Gorges Reservoir Region

This study conducted the first life cycle analysis for citrus residue (CR) management systems in China. The results indicated conventional waste treatment systems were not suitable for CR management in China. Although feed system seems to be a favourable option, the uncertainty analysis suggested valorisation system could achieved better performance in global warming, eutrophication and human toxicity. The environmental impacts of valorisation systems were more sensitive to energy consumption. For silage and single cell protein (SCP) system, the environmental impacts could be significantly reduced by improving the energy use efficiency or using more renewable energy. In comparison, although the environmental impacts of biorefinery system were less favourable than SCP and silage systems. The multiple extraction unit had less impact than reported values in other studies. Further research in biorefinery system can focus on increasing the energy efficiency of pre-treatment or reuse of extraction chemicals.

Mineral status and enteric methane production in dairy cows during different stages of lactation

BACKGROUND

Lactating dairy cows are the greatest livestock contributor of methane, a major global greenhouse gas (GHG). However, good feeding management with adequate mineral intake can offers an effective approach to maintaining high levels of milk production and the health of dairy cows over the entire course of lactation, while also helping to reduce methane emission. The study described here investigated the plasma concentrations of both macroelements (Ca, Na, K, Mg, P) and microelements (Zn, Cu, Fe, Mn), as well as enteric methane emission and milk composition in high-yielding dairy cows in different lactation periods. The experiment was performed on Holstein-Friesian dairy cows with the average milk yield of 41 (± 9) L/day in a Polish commercial farm with modern dairy systems. A total of thirty high-yielding dairy cows were randomly assigned into three groups differing by lactation stage: early stage (Early, days 25-100), middle stage (Middle, days 101-250), and late stage (Late, day 250 and later). Dietary treatment for all cows was a total mixture ration (TMR) with maize and alfalfa silage the main forage components.

RESULTS

The greatest milk yield and methane production were recorded in early-stage lactating cows, but the greatest methane intensity per kg of corrected milk was recorded in the late stage of lactation. Plasma concentrations of macroelements and microelements did not differ by lactation stages, but increased plasma concentrations of Zn and Fe and decreased plasma levels of Mg were noted during lactation. A positive correlation was found between plasma levels of Mg and other macroelements (Ca, Na, K), and between the concentrations of Fe and Zn, P in plasma, but no correlation between methane emission and mineral status was detected in the different lactation stages.

CONCLUSIONS

Our results showed different mineral requirements and enteric methane emissions in each lactation stage. The feeding strategy and mineral utilization were adequate to maintain the health, mineral status, and milk production of the Holstein cows during the entire lactation period, and suggest an effective way of reducing methane emission.

Little Difference in Milk Fatty Acid and Terpene Composition Among Three Contrasting Dairy Breeds When Grazing a Biodiverse Mountain Pasture

In the mountains, autochthonous and robust breeds are often used to valorize biodiverse grasslands. Along with their lower nutrient requirements, compared to specialized dairy breeds, they are expected to be better adapted to complex environments and valorize grasslands into dairy products of high quality. Therefore, the aim of the present study was to investigate the grazing selection of three contrasting dairy breeds on a biodiverse mountain pasture, and its consequences on milk fatty acid (FA) profile and prevalence of individual terpenes. A dual-purpose breed from the Italian Alps, the Valdostana Red Pied (Va), was compared to Montbéliardes (Mo), more specialized in milk production, and the highly specialized Holsteins (Ho). Diet selection was measured by scan-sampling, calculating selectivity indexes, and collecting simulated bites during two consecutive days in June (end of first grazing cycle) and July (second grazing cycle). Milk samples were collected at each milking during these experimental periods. Yield of milk and its fat and protein contents were measured. Milk FA and terpenes were analyzed by gas chromatographic methods. We tested the effects of breed, period and their interaction in a repeated mixed model, and calculated Pearson's correlations between behavioral data and milk FA as well as terpenes. The Va grazed less mature vegetation than Ho, but this difference was not sufficient to lead to a major breed effect on milk FA profile and prevalence of terpenes. However, the proportion of α-linolenic acid (C18:3 n-3) was always higher in the milk fat of Va than Ho (Mo were intermediary), but this without any correlation to grazing selection. This could be a consequence from a different metabolism concerning ruminal biohydrogenation, but must be further investigated. Finally, we confirmed previous studies that highlighted a link between milk quality and cows' grazing behavior, but here without differences among breeds. All cows adapted their behavior to the herbage evolution during the season, leading to higher proportions of unsaturated FA in July than June milks. Our study suggests that under mountain grazing conditions (biodiverse pasture and cows in late lactation), milk quality depends more on herbage composition than on cow breed.

A blend of essential oils improved feed efficiency and affected ruminal and systemic variables of dairy cows

This experiment evaluated the effect of a blend of essential oils (BEO) on intake, lactation performance, diet digestibility, ruminal fermentation profile, eating behavior, body thermoregulation, blood acid-base balance, and milk fatty acid profile of lactating cows. Twenty-eight Holstein cows were individually fed a standard diet for 14 d and treatments control or BEO (a microencapsulated blend of pepper extract containing capsaicin and pure forms of carvacrol, cinnamaldehyde, and eugenol; 150 mg/kg of diet dry matter) for 56 d. Significance was declared at P ≤ 0.05 and trends at 0.05 < P ≤ 0.10. Dry matter intake (DMI) was reduced (19.5 vs. 20.1 kg/d) and milk yield was increased (30.1 vs. 30.8 kg/d) by BEO, inducing improved milk to DMI ratio (1.53 vs. 1.62). Milk fat concentration tended to be increased by BEO, but total solids yield did not differ. There was a trend for increased total tract non-neutral detergent fiber organic matter digestibility with BEO. The molar proportion of acetate in ruminal fluid was reduced (51.4 vs. 57.8%) and that of propionate was increased (26.1 vs. 31.3%) by BEO. Ruminal microbial yield and total protozoa count in ruminal fluid did not differ. Cows fed BEO ingested a greater proportion of the daily intake in the morning (30.6 vs. 36.6%) and tended to ingest a lower proportion at night, tended to have longer meals, and had fewer meals per day (11.9 vs. 13.7) and larger meal size (1.5 vs. 1.7 kg of dry matter per meal). Blood urea-N and glucose concentrations did not differ. The BEO increased jugular blood oxygenation. The sweating rate on a hot and dry day was increased (160 vs. 221 g/m2/h) by BEO. The mean rectal and skin temperatures and respiration rate did not differ, but the proportion of rectal temperature measurements ≥39.2 °C was reduced by BEO at 1400 h (17.8 vs. 28.5%) and 2000 h (23.2 vs. 34.8%). The BEO increased the secretion (g/d) of 18:2 trans-10, cis-12 and the concentration of 18:0 iso fatty acids in milk fat. When one sample of milk from BEO cows was offered with two samples of milk from control, 59% of regular consumers of milk (n = 63) identified the odd sample correctly. The gain in feed efficiency induced by BEO was associated with reduced acetate-to-propionate ratio in ruminal fluid, altered eating behavior, lower frequency of high rectal temperature, and increased blood oxygenation. Essential oils had positive effects on ruminal fermentation and systemic variables of dairy cows.

Volatile aroma composition of distillates produced from fermented sweet and acid whey

Lactose within whey can be fermented and distilled to produce a potable distilled spirit. The aim of this study was to determine if acid and sweet whey types can be fermented and distilled using similar processes and to investigate differences in volatile aroma compounds for the 2 distillates. Fermentation and distillation of the 2 whey types progressed in a similar manner, using Kluyveromyces marxianus for the initial fermentation and a glass still fitted with a Vigreux column for the subsequent distillation. Ethanol content of the wash (fermented whey) varied considerably following each fermentation and ranged from 1.2 and 2.0% (wt/wt) with no clear trend between acid and sweet whey samples. Volatile aroma compounds were extracted using headspace solid-phase microextraction and identified via gas chromatography-mass spectrometry. Acid and sweet whey distillates contained unique volatile aromatic compounds, and significant differences in compound peak areas were observed. These differences may have an effect upon the organoleptic qualities of spirits produced from whey; therefore, whey source may be an important factor when fermenting and distilling whey.

Factors Influencing the Flavour of Bovine Milk and Cheese from Grass Based versus Non-Grass Based Milk Production Systems

There has been a surge in interest in relation to differentiating dairy products derived from pasture versus confined systems. The impact of different forage types on the sensory properties of milk and cheese is complex due to the wide range of on farm and production factors that are potentially involved. The main effect of pasture diet on the sensory properties of bovine milk and cheese is increased yellow intensity correlated to β-carotene content, which is a possible biomarker for pasture derived dairy products. Pasture grazing also influences fat and fatty acid content which has been implicated with texture perception changes in milk and cheese and increased omega-3 fatty acids. Changes in polyunsaturated fatty acids in milk and cheese due to pasture diets has been suggested may increase susceptibility to lipid oxidation but does not seem to be an issue to due increased antioxidants and the reducing environment of cheese. It appears that pasture derived milk and cheese are easier to discern by trained panellists and consumers than milk derived from conserved or concentrate diets. However, milk pasteurization, inclusion of concentrate in pasture diets, cheese ripening time, have all been linked to reducing pasture dietary effects on sensory perception. Sensory evaluation studies of milk and cheese have, in general, found that untrained assessors who best represent consumers appear less able to discriminate sensory differences than trained assessors and that differences in visual and textural attributes are more likely to be realized than flavour attributes. This suggests that sensory differences due to diet are often subtle. Evidence supports the direct transfer of some volatiles via inhalation or ingestion but more so with indirect transfer post rumen metabolism dietary components. The impact of dietary volatiles on sensory perception of milk and dairy products obviously depends upon their concentration and odour activity, however very little quantitative studies have been carried out to date. Some studies have highlighted potential correlation of pasture with enhanced “barny” or “cowy” sensory attributes and subsequently linked these to accumulation of p-cresol from the metabolism of β-carotene and aromatic amino acids or possibly isoflavones in the rumen. p-Cresol has also been suggested as a potential biomarker for pasture derived dairy products. Other studies have linked terpenes to specific sensory properties in milk and cheese but this only appears to be relevant in milk and cheese derived from unseeded wild pasture where high concentrations accumulate, as their odour threshold is quite high. Toluene also a product of β-carotene metabolism has been identified as a potential biomarker for pasture derived dairy products but it has little impact on sensory perception due to its high odour threshold. Dimethyl sulfone has been linked to pasture diets and could influence sensory perception as its odour threshold is low. Other studies have linked the presence of maize and legumes (clover) in silage with adverse sensory impacts in milk and cheese. Considerably more research is required to define key dietary related impacts on the flavour of milk and cheese.

Performance and methane emissions in dairy cows fed oregano and green tea extracts as feed additives

Plant extracts have been proposed as substitutes for chemical feed additives due to their potential as rumen fermentation modifiers and because of their antimicrobial and antioxidant activities, possibly reducing methane emissions. This study aimed to evaluate the use of oregano (OR), green tea extracts (GT), and their association as feed additives on the performance and methane emissions from dairy between 28 and 87 d of lactation. Thirty-two lactating dairy cows, blocked into 2 genetic groups: 16 Holstein cows and 16 crossbred Holstein-Gir, with 522.6 ± 58.3 kg of body weight, 57.2 ± 20.9 d in lactation, producing 27.5 ± 5.0 kg/cow of milk and with 3.1 ± 1.8 lactations were evaluated (means ± standard error of the means). Cows were allocated into 4 treatments: control (CON), without plant extracts in the diet; oregano extract (OR), with the addition of 0.056% of oregano extract in the dry matter (DM) of the diet; green tea (GT), with the addition of 0.028% of green tea extract in the DM of the diet; and mixture, with the addition of 0.056% oregano extract and 0.028% green tea extract in the DM of the diet. The forage-to-concentrate ratio was 60:40. Forage was composed of corn silage (94%) and Tifton hay (6%); concentrate was based on ground corn and soybean meal. Plant extracts were supplied as powder, which was previously added and homogenized into 1 kg of concentrate in natural matter, top-dressed onto the total mixed diet. No treatment by day interaction was observed for any of the evaluated variables, but some block by treatment interactions were significant. In Holstein cows, the mixture treatment decreased gross energy and tended to decrease the total-tract apparent digestibility coefficient for crude protein and total digestible nutrients when compared with OR. During the gas measurement period, GT and OR increased the digestible fraction of the ingested DM and decreased CH₄ expressed in grams per kilogram of digestible DMI compared with CON. The use of extracts did not change rumen pH, total volatile fatty acid concentration, milk yield, or most milk traits. Compared with CON, oregano addition decreased fat concentration in milk. The use of plant extracts altered some milk fatty acids but did not change milk fatty acids grouped according to chain length (short or long), saturation (unsaturated or saturated), total conjugated linoleic acids, and n-3 and n-6 contents. Green tea and oregano fed separately reduced gas emission in cows during the first third of lactation and have potential to be used as feed additives for dairy cows.

Variation of terpenes in milk and cultured cream from Norwegian alpine rangeland-fed and in-door fed cows

The terpene content of milk and cream made from milk obtained from cows fed indoors, and by early or late grazing, in alpine rangeland farms in Norway, were analysed for three consecutive years. The main terpenes identified and semi-quantified were the monoterpenes β-pinene, α-pinene, α-thujene, camphene, sabinene, δ-3-carene, d-limonene, γ-terpinene, camphor, β-citronellene, and the sesquiterpene β-caryophyllene. The average total terpene content increased five times during the alpine rangeland feeding period. The terpenes α-thujene, sabinene, γ-terpinene and β-citronellene were only detected in milk and cultured cream from the alpine rangeland feeding period and not in samples from the indoors feeding period. These four terpenes could be used, as indicators, to show that milk and cultured cream originate from the alpine rangeland feeding period. The terpenes did not influence the sensorial quality of the milk or the cultured cream.

Chemistry and multibeneficial bioactivities of carvacrol (4-isopropyl-2-methylphenol), a component of essential oils produced by aromatic plants and spices

Aromatic plants produce organic compounds that may be involved in the defense of plants against phytopathogenic insects, bacteria, fungi, and viruses. One of these compounds, called carvacrol, which is found in high concentrations in essential oils such as oregano, has been reported to exhibit numerous bioactivities in cells and animals. This integrated overview surveys and interprets our present knowledge of the chemistry and analysis of carvacrol and its beneficial bioactivities. These activities include its antioxidative properties in food (e.g., lard, sunflower oil) and in vivo and the inhibition of foodborne and human antibiotic-susceptible and antibiotic-resistant pathogenic bacteria, viruses, pathogenic fungi and parasites, and insects in vitro and in human foods (e.g., apple juice, eggs, leafy greens, meat and poultry products, milk, oysters) and food animal feeds and wastes. Also covered are inhibitions of microbial and fungal toxin production and the anti-inflammatory, analgesic, antiarthritic, antiallergic, anticarcinogenic, antidiabetic, cardioprotective, gastroprotective, hepatoprotective, and neuroprotective properties of carvacrol as well as metabolic, synergistic, and mechanistic aspects. Areas for future research are also suggested. The collated information and suggested research might contribute to a better understanding of agronomical, biosynthetic, chemical, physiological, and cellular mechanisms of the described health-promoting effects of carvacrol, and facilitate and guide further studies needed to optimize the use of carvacrol as a multifunctional food in pure and encapsulated forms, in edible antimicrobial films, and in combination with plant-derived and medical antibiotics to help prevent or treat animal and human diseases.

Immune and production responses of dairy cows to postruminal supplementation with phytonutrients

This study investigated the effect of phytonutrients (PN) supplied postruminally on nutrient utilization, gut microbial ecology, immune response, and productivity of lactating dairy cows. Eight ruminally cannulated Holstein cows were used in a replicated 4×4 Latin square. Experimental periods lasted 23 d, including 14-d washout and 9-d treatment periods. Treatments were control (no PN) and daily doses of 2g/cow of either curcuma oleoresin (curcumin), garlic extract (garlic), or capsicum oleoresin (capsicum). Phytonutrients were pulse-dosed into the abomasum of the cows, through the rumen cannula, 2 h after feeding during the last 9 d of each experimental period. Dry matter intake was not affected by PN, although it tended to be lower for the garlic treatment compared with the control. Milk yield was decreased (2.2 kg/d) by capsicum treatment compared with the control. Feed efficiency, milk composition, milk fat and protein yields, milk N efficiency, and 4.0% fat-corrected milk yield were not affected by treatment. Rumen fermentation variables, apparent total-tract digestibility of nutrients, N excretion with feces and urine, and diversity of fecal bacteria were also not affected by treatment. Phytonutrients had no effect on blood chemistry, but the relative proportion of lymphocytes was increased by the capsicum treatment compared with the control. All PN increased the proportion of total CD4(+) cells and total CD4(+) cells that co-expressed the activation status signal and CD25 in blood. The percentage of peripheral blood mononuclear cells (PBMC) that proliferated in response to concanavalin A and viability of PBMC were not affected by treatment. Cytokine production by PBMC was not different between control and PN. Expression of mRNA in liver for key enzymes in gluconeogenesis, fatty acid oxidation, and response to reactive oxygen species were not affected by treatment. No difference was observed due to treatment in the oxygen radical absorbance capacity of blood plasma but, compared with the control, garlic treatment increased 8-isoprostane levels. Overall, the PN used in this study had subtle or no effects on blood cells and blood chemistry, nutrient digestibility, and fecal bacterial diversity, but appeared to have an immune-stimulatory effect by activating and inducing the expansion of CD4 cells in dairy cows. Capsicum treatment decreased milk yield, but this and other effects observed in this study should be interpreted with caution because of the short duration of treatment.