Invited review: Human, cow, and donkey milk comparison: Focus on metabolic effects

Milk is an important food of the daily diet. Many countries include it in their dietary recommendations due to its content in several important nutrients that exert beneficial effects on human health. Human milk is a newborn's first food and plays an important role in the growth, development, and future health of every individual. Cow milk is the type of milk most consumed in the world. However, its relatively high content of saturated fats raises concerns about potential adverse effects on human health, although epidemiological studies have disproved this association. Indeed, dairy consumption appear to be linked to a lower risk of mortality and major cardiovascular disease events. In the last few years many researchers have begun to focus their attention on both the production and quality of cow milk as well as the analysis of milk from other animal species to evaluate their effect on human health. The need to investigate the composition and metabolic effects of milk from other animal species arises from the adverse reactions of individuals in several groups to certain components of cow milk. It has emerged that donkey milk compared with that of other animal species, is the nearest to human milk and an excellent substitute for it. Milk from various animal species shows substantial differences in nutritional composition and distinct metabolic effects. In this review, we discussed the main compositional features and metabolic effects of 3 types of milk: human, cow, and donkey milk.

Effect of a high forage : concentrate ratio on milk yield, blood parameters and oxidative status in lactating cows

A feeding strategy that requires a forage:concentrate ratio equal to 70:30, with at least five different herbs in the forage and the use of silages prohibited, has recently been introduced in Italy. Despite the benefits in terms of human health (lower ω6:ω3 ratio, higher conjugated linoleic acid level) of the obtained milk, little information regarding the possible effects on cows’ health is available. The aim of this study was to evaluate the effects of such a feeding strategy in dairy cows (90 days in milk at the beginning of the trial) on milk yield and composition, and blood metabolic profile, including the evaluation of oxidative stress. The proposed feeding strategy, compared with a semi-intensive strategy, resulted in an improvement of animal oxidative status (lower levels of reactive oxygen metabolites, higher levels of antioxidant potential and anti-reactive oxygen metabolites) and a significant increase of milk urea only in the first part of the trial. No differences in milk yield and composition were detected throughout the trial.

Comparison of nutritional and antinutritional traits among different species (Lupinus albus L., Lupinus luteus L., Lupinus angustifolius L.) and varieties of lupin seeds

In order to promote the use of lupin in pig nutrition, in this research the nutritional characteristics (i.e. dietary fibre, alkaloid and fatty acid profile) and the in vitro gas production of 12 lupin varieties grown in the Mediterranean basin and belonging to three lupin species (Lupinus albus, Lupinus angustifolius and Lupinus luteus) were assessed. Four varieties of L. albus (Asfer, Lublanc, Lutteur and Multitalia) were grown in South Campania. Three varieties of L. luteus (Dukat, Mister and Taper), three of L. angustifolius (Jindalee, Sonet and Wonga) and two of L. albus (Rosetta and Luxor) were grown in Eastern Sicily. Lupinus albus varieties showed interesting nutritional and dietetic characteristics (i.e. high protein and low fibre content); the lipid fraction, rather elevated, is well represented by monounsaturated fatty acids (544 g/kg), whereas saturated fatty acids (SFAs) are less represented (167 g/kg) and the n-3/n-6 ratio (0.510) is the most favourable. Lupinus luteus varieties presented the most remarkable dietetic aspects, in terms of polyunsaturated fatty acid (PUFA) content (569 g/kg), n-6 PUFA series (490 g/kg), UFA/SFA (5.24) and PUFA/SFA (3.56) ratios and atherogenic (0.059) and thrombogenic (0.100) indices and very low alkaloid content (1.07 mg per 100 g). Lupinus angustifolius varieties showed the least interesting nutritional and dietetic characteristics: low protein and fat content, high fibre level, high SFA amount (248 g/kg) and the lowest favourable nutritional indices (IA: 0.164 and IT: 0.334). Regarding the fermentation process, in L. albus, the tendency to increase the rate of gas production during the early stages of fermentation suggests that the high presence of alkaloids did not affect the in vitro degradability, production of short-chain fatty acids and fermentation process, probably due to their concentration and/or water solubility. Lupinus angustifolius and L. luteus showed intermediate and slightly worse in vitro fermentation patterns respectively. From a nutritional and dietetic point of view, lupin may represent an interesting alternative to soya bean in pig feeding.

Regulation of Stearoyl Coenzyme A Desaturase 1 Gene Promoter in Bovine Mammary Cells

Stearoyl-Coenzyme A desaturase 1 (SCD1) belongs to the fatty acid family of desaturases. In lactating ruminants, the SCD1 protein is highly expressed in the mammary gland and is relevant for the fatty acid composition of milk and dairy products. Bovine mammary epithelial cells (BME-UV1), cultured in vitro, have been proposed as a model to reproduce the biology of the mammary gland. The present study was designed to investigate the responsiveness of bovine SCD1 promoter to serum, insulin, oleic acid, and NFY transcription factor in BME-UV1 cells. A luciferase-based reporter assay was used to monitor the transcriptional activity of the SCD1 promoter region in BME-UV1 cells treated or not with insulin and/or oleic acid. The level of endogenous SCD1 mRNA was evaluated by Real time PCR. Insulin (20 ng/mL) induced a 2.0 to 2.5-fold increase of SCD1 promoter activity. Additionally, the effect of insulin was inhibited by oleic acid, serum components, and NFY enforced expression. Serum and NFY showed no synergistic or additive effect on SCD1 promoter activity suggesting that they repress SCD1 transcription through the same responsive element.

Meat quality of buffalo young bulls fed faba bean as protein source

Sixteen Italian Mediterranean Buffalo young bulls were divided into two groups fed isoprotein and isoenergy diets and only differing for protein source of concentrate: faba bean (FB) vs soybean (SB). Animals were slaughtered at 350 kg BW. Meat from FB group showed significantly lower fat, protein, cholesterol and saturated fatty acids than SB group. Significant differences were also found between the three muscles analysed [Longissimus thoracis (LT), Semitendinosus (ST) and Iliopsoas plus Psoas minor (IP)]. ST showed the most favourable fatty acids profile: lower SFA, higher PUFA, MUFA, ω-3, ω-6, CLA and, consequently, lower values for both atherogenic and thrombogenic indexes. Results showed that faba bean can be used as a protein source alternative to soybean in the diet of young buffalo bulls for the production of high quality meat.

Fermentation kinetics of sainfoin hay with and without PEG

The in vitro gas production technique was applied to evaluate the biological activity of tannins in sainfoin (Onobrychis viciifolia Scop.) hay cut at four progressive phenological stages. The buffalo (Bubalus bubalis) rumen fluid was used as inoculum, polyethylene glycol (PEG) was added as specific binding agent and an alfalfa hay (AH) was used as control. All samples were analysed for chemical composition and condensed tannin (CTs). According to the phenological stage of sainfoin, crude protein gradually decreased [from 219 to 122 g/kg dry matter (DM)] and neutral detergent fibre (NDF) increased (from 391 to 514 g/kg DM). Condensed tannins showed the highest value at the first phenological stage [31.5 mg catechin equivalents (CE)/g DM], and their level significantly decreased at the subsequent growth stages. Gas production and fermentation rate were significantly affected by substrate type and PEG addition. The first stage of sainfoin showed the lowest value of gas and volatile fatty acids production and the slowest fermentation kinetics compared with the other samples, when incubated without PEG, because of the CTs effect. The incubation with PEG improved the fermentation process of the first stage of sainfoin, but no effect was registered on AH, where CTs were not detected. Among the sainfoin samples, the slowest kinetics with PEG was observed in the hay harvested at the fourth stage, probably due to its chemical composition. The use of PEG allowed to verify the effect of tannins on the in vitro fermentation characteristics of sainfoin hay.

Influence of replacing corn silage with barley silage in the diets of buffalo cows on milk yield and quality

A 150-day trial was carried out on 40 Italian Mediterranean buffalo cows that, immediately after calving, were equally divided into two homogeneous groups (M and O) based on the number of calving events and previous milk yield. The animals were fed (16 kg dry matter (DM)/head) two isoenergy/isoprotein diets (NEl: 6.39 MJ/kg DM; 15.4 CP% DM), composed of corn (diet M) or barley silage (diet O) concentrate, alfalfa hay, and a vitamin-mineral supplement. The fermentation characteristics of both silage diets were evaluated by an in vitro gas production technique, and their nutritional values were calculated as follows: NEl (MJ/kg DM) = 0.54 + 0.0959 GP + 0.0038 CP + 0.0001733 CP(2), where GP is the gas production after 24 h of incubation (ml/200 mg DM) and CP is the protein content of silage (g/kg DM). The nutritional values of the silages were slightly different (4.16 vs. 4.14 MJ/kg DM for M and O, respectively) likely due to the high content of hemicellulose in the O diet (22.0 vs. 16.9%). Average milk yield did not differ between the groups; instead, milk fat (8.39 vs. 9.06%; P < 0.01) and protein (4.41 vs. 4.60%; P < 0.01) levels were significantly higher in the O group. The results elicit great interest in southern Italy where corn cultivation is adversely affected by the high cost of irrigation.

Prediction of rabbit caecal fermentation characteristics from faeces by in vitro gas production technique: roughages

To find equations able to estimate the fermentation characteristics of the caecum from that of faeces, caecal content and faeces of 10 hybrid Hyla rabbits were used as inocula for an in vitro gas production trial. About 1 g of 12 roughages, 11 hays (ryegrass, alfalfa, sulla, oat, vetch, sulla-lolium, vetch-oat, sulla-oat, clover, ryegrass-clover, sulla-vetch-oat) and a wheat straw, was weighed, in triplicate per inoculum, in 120-ml flasks; 75 ml of anaerobic medium and 4 ml of reducing solution were added and the flasks were placed at 39 degrees C. Caecal content and faeces were diluted respectively 1:2 (CI) and 1:8 (FI) with anaerobic medium and were introduced into their respective flasks (10 ml). Gas production was recorded 20 times at 2-24 h intervals throughout fermentation (120 h). The fermentation characteristics (i.e. degraded organic matter, OMd; potential gas production, A; maximum fermentation rate, R(max); volatile fatty acid, VFA; ammonia, NH(3)) were studied by inocula and substrates. The two inocula did not differ in OMd but CI produced significantly higher gas (A, 213.1 vs. 199.4 ml/g, respectively, for CI and FI, p < 0.01) in less time (R(max), 3.08 vs. 2.24 ml/h, respectively, for CI and FI, p < 0.01). CI also produced higher levels of total VFA (57.86 vs. 46.70 mmol/g OM, respectively, for CI and FI, p < 0.01) and showed a higher branched chain proportion (0.023 vs. 0.018, respectively, for CI and FI, p < 0.01). For some parameters (as OMd pH and propionate) the equations for the estimation of caecal fermentation characteristics from that of faeces were accurate (R(2) > 0.8828) and reliable (CV < 10.78%) suggesting that faeces can be successfully used for the estimation of these parameters.

Use of faeces as an alternative inoculum to caecal content to study in vitro feed digestibility in domesticated ostriches (Struthio camelus var. domesticus)

1. In order to find an alternative source of inoculum to caecal content for studying the in vitro feed digestibility in domesticated ostriches (Struthio camelus var. domesticus), caecal content and faeces of 4 male birds were used as inocula for an in vitro gas production trial. 2. About 1 g of each of 5 substrates (maize silage, CS; alfalfa hay, AH; barley, BG; soybean meal, SM; beet pulp, BP) was weighed, in quadruplicate per inoculum, in 120 ml flasks; 75 ml of anaerobic medium and 4 ml of reducing solution were added and flasks were kept at 39 degrees C. Caecal content and faeces were diluted respectively 1 : 2 (CI) and 1 : 4 (FI) with an anaerobic medium and were injected into the respective flasks (10 ml). 3. Gas production was recorded 22 times up to 120 h of incubation and fermentation characteristics (for instance, degraded organic matter, OMd; potential gas production, A; maximum fermentation rate, Rmax; time at which it is reached, Tmax; pH; volatile fatty acid, VFA; ammonia) were studied for each inoculum and substrate. 4. CI and FI showed significant differences in Tmax (16.37 vs 18.47 h, respectively), propionic (16.47 vs 12.07 mmoles/l) and butyric acid (6.50 vs 7.98 mmoles/l) and ammonia concentration (17.18 vs 19.95 mmoles/l). The substrates, according to their chemical composition, showed different fermentation characteristics. However, the regression equations able to estimate some fermentation characteristics of the caecum from those of faeces were statistically significant and showed R2-values ranging from 0.87 to 0.99. 5. The differences in fermentation pathways of the two inocula did not appear to influence the rate and extent of OM digestion. Faecal fermentation predicted rates and extent of OM digestion by caecal fermentation in ostriches; consequently, the faeces could be considered as an alternative to caecal content to study feed digestibility in the species, although there is a need to undertake further research.

Use of two different dietary energy and protein contents to define nutritive requirements of lactating buffalo cows

Two total mixed rations, differing in energy and protein concentrations (diet A: 6.1 MJ/kg DM of NE(l), 112.5 g/kg DM of metabolizable protein, MP, and 101.7 g of protein digestible at the intestinal level, PDI, vs. diet B: 6.4 MJ, 95.1 g of MP, 78.9 g of PDI) were administered ad libitum for 1 year to two groups of 12 buffaloes in which the partial monthly turnover of animals allowed the lactation stage to be maintained close to 160 days. The diets were formulated to obtain, with a daily intake of about 15.5 kg of DM, a balanced energy supply but an excess of protein (diet A); the opposite occurred with diet B. The average dry matter intake recorded during the trial was 14.5 kg for diet A and 15.0 kg for diet B. Milk production was similar for both groups (7.94 kg vs. 7.95 kg). The diet with a higher protein concentration brought about a significant increase in protein, casein and non-protein nitrogen contents in the milk. A significant increase in milk fat percentage was observed when the animals were fed the diet with a higher energy concentration. The serum urea concentration (8.62 mm/l) of buffaloes fed diet A was outside the physiological range for lactating buffaloes. The energy and protein conversion efficiencies for milk production were more favourable when their supplies were balanced: 3.58 MJ of NE(l)/kg of FPCM for diet A; 2.50 g of MP or 2.07 g of PDI/g of protein milk for diet B. Moreover, when the requirements were satisfied, greater energy or protein supplies failed to induce significant changes in milk yield and quality. Finally, regarding the great differences between estimated MP requirements and those recorded during the trial, the authors suggest that the equations used in the CPM-Dairy software, formulated for dairy cows, are not applicable in buffaloes.

Genetically modified soya bean in rabbit feeding: detection of DNA fragments and evaluation of metabolic effects by enzymatic analysis

The presence of DNA fragments in tissues from rabbits given genetically modified (GM) soya-bean meal (solvent extracted) was investigated by using the polymerase chain reaction (PCR) approach. Moreover, the possible effects on cell metabolism were evaluated by determination of several specific enzymes in serum, heart, skeletal muscle, liver and kidney. The chloroplast sequence for tRNA Leu by using the Clor1/Clor2 primers designed on chloroplast trnL sequence was clearly detected. On the contrary, two couples of species specific primers for conventional (Le1-5/Le 1-3 which amplifies the soya bean lectin gene) and genetically modified (35S1/35S2 which amplifies the 35S CMV promoter that is present in the genomic structure of GM soya bean) soya bean were not found in all samples. No differences in enzyme levels were detected in serum, but a significant increase of lactic dehydrogenase, mainly concerning the LDH1 isoenzyme was found in particular in kidney and heart but not in the muscle, thus suggesting a potential alteration in the local production of the enzyme. Finally, no significant differences were detected concerning body weight, fresh organ weights and no sexual differences were detected.