Effects of age on composition and quality of muscle Longissimus thoracis of the Omani Arabian camel (Camelus dromedaries)

The aim of this study was to determine the effects of age on chemical composition and quality characteristics of the Arabian one-humped camel’s meat. Samples of longissimus thoracis (between the 10th and the 13th rib of the left side) were randomly collected from 21 Omani intact male camels of three different age groups: group 1 (1–3 years), group 2 (3–5 years) and group 3 (6–8 years). Samples were chilled (1–3 °C) for 48 h. Moisture, crude protein, fat and ash were determined on freeze dried ground muscle. Mineral contents were determined using an Inductively coupled plasma emission spectrometer (ICP). Meat quality including ultimate muscle pH, Warner–Bratzler shear force, sarcomere length, myofibrillar fragmentation index, expressed juice, cooking loss percent, and colour L^*, a^*, b^* were measured using standard methods.

The moisture, protein, fat and ash ranged from 64.4% to 76.7%; 18.6% to 25.0%, 1.1% to 10.5% and 1.0% to 1.4% on dry matter basis, respectively. The Ca, Mg, Na, K, P, Cad, Cr, Ni, Pb, Co, Mo, Be and V ranged from, 9.2 to 46.6, 24.7 to 57.3, 104.7 to 257.0, 471.4 to 1053.0, 249.9 to 584.0, 0.005 to 0.024, 0.020 to 0.410, 0.016 to 0.187, 0.010 to 0.299, 0.010 to 0.018, 0.050 to 0.470, 0.005 to 0.030 and 0.013 to 0.141 mg/100 g on dry matter basis, respectively. The percentage of protein decreased and that of fat increased with increasing camel age. The ultimate pH, shear force, sarcomere length, fragmentation index, expressed juice, cooking loss, lightness (L^*), redness (a^*) and yellowness (b^*) ranged from 5.46 to 6.64, 4.25 to 17.82, 0.96 to 2.50, 55.91 to 94.81,19.50 to 33.63, 13.18 to 29.88, 27.86 to 43.21, 10.46 to 22.81, and 4.63 to 10.11, respectively. Muscles of younger camels (group 1) had significantly (P < 0.05) lower shear force value, ultimate pH and higher sarcomere length, fragmentation index, expressed juice, cooking loss, and lightness color (L^*) by 48%, 3.4%, 43%, 25%, 28%, 14%, and 16% than those collected from older camels (group 3), respectively. Values of middle age camels (group 2) camels were in-between. This study confirmed that camel meat is healthy and nutritious as it contains low fat as well as being a good source of minerals. Age is an important factor in determining meat quality and composition.     

Stereospecific analysis of triacylglycerols in camel (Camelus dromedarius) milk fat

In the lipid fraction of camel (Camelus dromedarius) milk the percentage of saturated fatty acids (SFAs) was 62.8% with a content of palmitic acid of 28.5%. The unsaturated fatty acid (UFA) fraction was dominated by oleic and palmitoleic acids. Enzyme digestion and chemical degradation methods were used to determine the intramolecular fatty acid (FA) composition and then the intermolecular FA distribution in the three sn-positions of the triacylglycerols of the camel milk. FAs showed a specific preference for a particular position: in all samples studied, SFAs were prevalently esterified in the sn-2 position, while UFAs occupied mainly the sn-1 and sn-3 position. As the carbon chain lengthened from 8 to 16 the percentages of SFAs decreased in the sn-2 position and increased in the outer positions. Such data indicated that the length of the carbon chain could be a discriminating factor in the acylation process of SFAs.     

Studies on the supply of immunoglobulin G to newborn camel calves (Camelus dromedarius)

A major problem in camel productivity is the high mortality rate of camel calves in the first 3 months. The causes for mortality are mainly poor management practice and infectious diseases. The purpose of this research, carried out on a ranch in Kenya, was to determine the immunoglobulin G (IgG) concentration in camel colostrum as well as the extent of the calves' passive immunization by maternal antibodies. IgG concentration in colostrum and in the serum of the calf were measured during the first 3 d of life. Evaluation was carried out by comparing the respective values with those for horses and cattle. The average IgG concentration in the camel colostrum was higher than that found in literature for horses and cattle. IgG concentration in the serum of the camel calves reached its maximum 24 h after birth. In 39% of the examined calves, this maximum concentration was below 4 g/l, which is considered to be the critical value in horses and cattle. 61% of the calves achieved an IgG concentration of over 4 g/l. Since there is no correlation between IgG level in colostrum and early mortality, the results indicate that low colostrum intake during the first 24 h of life and not low IgG concentration in colostrum is presumably one of the main causes of early calf mortality. Therefore, it was recommended that the care of the newborn calves by herdsmen should be improved.     

Immunochemical quantification of heat denaturation of camel ( Camelus dromedarius ) whey proteins

The major whey proteins IgG, serum albumin and alpha-lactalbumin were purified from camel milk using gel permeation and ion-exchange chromatography. Specific antisera against each of them were raised and used to quantify their heat denaturation in early or mature milk over a range of 60-90 degrees C for 10-60 min using the single radial immunodiffusion technique. The heat denaturation midpoints for the mature milk heated 30 min were 67.2, 73.0 and 77.5 degrees C for IgG, albumin and alpha-lactalbumin respectively. The early milk was more sensitive to heat treatment with coagulation at low temperature and heat denaturation midpoints of 64.8, 71.6 and 72.6 degrees C respectively. This difference was related to the high IgG content of the early milk (12.6 mg/ml v. 0.5 mg/ml for the mature milk) and stresses the importance of monitoring the IgG level of milk to assess the absence of colostrum.     

Comparison of uteroplacental glycosylation in the camel (Camelus dromedarius) and alpaca (Lama pacos)

The recent birth of a camel-llama hybrid, after numerous failed attempts, has prompted an investigation into the glycosylation of apposing fetal and maternal tissues of pregnant camels and alpacas. This study was undertaken to determine whether interspecies differences in glycans are factors that may account in part for the difficulty in producing a viable hybrid. Specimens of camel placentae from day 60 to day 375 of gestation and alpaca placentae from day 22 to term (approximately 345 days) were fixed and embedded in resin, and sections were stained with a panel of 19 biotinylated lectins and an avidin--peroxidase revealing system. Several qualitative interspecies differences in tissue glycosylation were found, mainly in the trophoblast, and especially with respect to bi/tri-antennary bisected N-glycan, fucosylated structures, beta-galactosyl residues and sialyl termini. In the maternal uterine epithelium, differences were found mainly in bi/tri-antennary bisected complex N-glycan and beta-galactosyl residues, indicating that there is more conservation of glycosylation in maternal tissues compared with trophoblast. There were also many quantitative differences in the distribution of glycans. It is possible that a failure to effect the normal glycan--glycan complementation that occurs at the cell surface between maternal and fetal tissues during the implantation processes of apposition and adhesion may account in part for the difficulty in establishing a viable pregnancy between these two species.     

Fatty acid composition of the meat and fat of the one-humped camel (camelus dromedarius)

The fatty acid composition of lean raw meat taken from the hind leg of seven young (1-3 years of age) male one-humped camels (Camelus dromedarius) has been determined by capillary gas-liquid chromatography; fat samples taken from the hump of these seven camels were also analysed. The saturated fatty acids in the meat account for 51·5% of the total fatty acids, while the monosaturated and polyunsaturated chains constitute 29·9 and 18·6%, respectively. The major fatty acids in camel meat are palmitic (26·0%), oleic (18·9%) and linoleic (12·1%), with smaller amounts of other fatty acids, both normal and branched, that range in chain lengths from C(14) to C(22). The fatty acids of dromedary fat are dominated by saturated even-numbered chains with smaller amounts (5·4%) of odd-numbered normal and branched chains. The main fatty acid of the hump fat is palmitic (34·4%) followed by oleic (28·2%), myristic (10·3%) and stearic (10·0%).     

Effect of season on contractile and metabolic properties of desert camel muscle (Camelus dromedarius)

Thirty fattened one humped desert camels were used to examine the effect of season on contractile and metabolic properties of Longissimus thoracis (LT) muscle. Ten camels were slaughtered according to seasons of the year (winter, summer and autumn). Season significantly influenced muscle chemical composition, ultimate pH (pHu) and color. Activities of metabolic enzymes were higher during autumn season compared to summer and winter for phosphofructokinase (+ 64% compared to both seasons) and for isocitrate dehydrogenase (+ 35% and + 145% in autumn vs. summer and winter, respectively). Quantification of muscle myosin heavy chain isoforms by SDS-PAGE electrophoresis showed only presence of type I and type IIa MyHC in camel muscle and indicated high proportion in winter for type I and in autumn for type IIa with respect to other seasons. Several correlations between different MyHC proportions and enzyme activities were reported. These findings indicated that muscle characteristics in camels are influenced by season.     

Chemical characterisation of oligosaccharides in commercially pasteurised dromedary camel (Camelus dromedarius) milk

It has been suggested that bactrian camel milk and colostrum may be a good source of biologically significant oligosaccharides but, although the oligosaccharides found in bactrian camel milk and colostrum have been characterised, those in dromedary camel milk have not. In this study, seven oligosaccharides from commercially available pasteurised dromedary camel milk were characterised using ¹H nuclear magnetic resonance spectroscopy. The following oligosaccharides were detected: Gal(β1-3)Gal(β1-4)Glc (3′-galactosyllactose), Gal(β1-4)GlcNAc(β1-3)[Gal(β1-4)GlcNAc(β1-6)]Gal(β1-4)Glc (lacto-N-neohexaose), Neu5Ac(α2-3)Gal(β1-4)Glc (3′-sialyllactose), Neu5Ac(α2-6)Gal(β1-4)Glc (6′-sialyllactose), Neu5Ac(α2-3)Gal(β1-3)Gal(β1-4)Glc (sialyl-3′-galactosyllactose), Neu5Ac(α2-3)Gal(β1-3)[Gal(β1-4)GlcNAc(β1-6)]Gal(β1-4)Glc (sialyllacto-N-novopentaose a) and Neu5Ac(α2-6)Gal(β1-4)GlcNAc(β1-3)[Gal(β1-4)GlcNAc(β1-6)]Gal(β1-4)Glc (monosialyllacto-N-neohexaose).     

Milk production and feeding behavior in the camel (Camelus dromedarius) during 4 watering regimens

Camels survive and produce milk during recurrent prolonged hot and dry periods. The objective was to evaluate how different watering intervals affected milk production and feeding. Eight lactating camels (Camelus dromedarius) were recruited and subjected to 4 watering regimens in a Latin square design experiment performed at Haramaya University in Ethiopia. Each regimen lasted 16 d with 5 d of daily watering between periods: water was offered at 1315 h once daily (W1); on d 4, 8, 12, and 16 (W4); on d 8 and 16 (W8); and on d 16 (W16). One camel became sick in the second period and its results were excluded. Camels were kept in a pen with minimal shade and a noon temperature of 30.9 ± 0.1°C. They had free access to hay and were offered 2 kg of concentrates 3 times daily. At noon on d 1, 4, 8, 12, and 16, a blood sample was taken from the jugular vein before watering. All calves were kept together in a separate pen. Morning and afternoon calves stimulated milk let-down before the camels were hand-milked, after which the calves suckled, emptying the udder. Camels maintained the milk volume during water deprivation for about 1 wk, but they produced less milk during the second week during W16. Morning milk osmolality increased from 315 ± 3 on d 1 to 333 ± 3 mosm/kg on d 4 during W4 and from 321 ± 3 on d 1 to 342 ± 3 mosm/kg on d 8 during W8. After watering at 1315 h, milk osmolality decreased to 316 ± 3 and 323 ± 3 mosm/kg, respectively, the same afternoon and then increased during recurrent water deprivation to 338 ± 3 (W4) and 347 ± 3 mosm/kg (W8) on d 16, respectively. During W16, osmolality increased from 318 ± 3 to 336 ± 3 mosm/kg during the first 4 d of water deprivation, but during the remaining 12 d the further rise in osmolality was not higher compared with that on d 4. The change in milk osmolality was linearly correlated to plasma osmolality (r = 0.8), but milk lactose content did not increase. Contrary to widespread belief, camels did not dilute their milk when dehydrated. Instead milk osmolality increased in parallel to blood osmolality. This study provides further support to earlier observations on camels’ adaptation to their environment.     

The influences of carcass weight and depot on the fatty acid composition of fats of suckling Manchego lambs

The effects of carcass weight (<5.5 kg, 5.5–6.5 kg, ⩾6.5 kg) of Manchego suckling lambs, type of fat depot of the leg (subcutaneous, intermuscular and intramuscular) and muscle (m. longissimus dorsi (LD) or m. quadriceps femoris (QF)) on the fatty acid composition were studied. Carcass fatness increased with increasing carcass weight. However, few differences in fatty acid proportion were observed between the three carcass weight groups. The lightest carcasses had lower proportions of myristic (C14:0) and palmitoleic (C16:1) acid and higher proportions of stearic (C18:0) acid, desirable fatty acids (DFA) (C18:0 + total unsaturated fatty acid (TUFA)) and a greater nutritive value ((C18:0 + C18:1)/C16:0). The fatty acid composition of subcutaneous and intermuscular fat depots of the leg were similar, whereas the intramuscular fat depot was different from both of these, since it had a lower proportion of saturated fatty acids (SFA), a greater proportion of TUFA, higher PUFA/SFA and n − 6/n − 3 ratios, and greater DFA and nutritive values. The intramuscular fat of the LD was more saturated than QF, higher SFA, and had lower value of PUFA/SFA ratio and DFA. These results indicated that the intramuscular fat quality of the leg was better than subcutaneous and intermuscular fat depots and also that intramuscular fat displayed better attributes of quality (lower SFA, higher TUFA, and greater PUFA/SFA ratio and DFA as well) than intramuscular fat of the LD from the consumer health standpoint. Despite carcass weight affected carcass fatness, it did not seem to influence the proportions of saturated or polyunsaturated fatty acids. For this reason, carcass weight probably had little effect on the organoleptic characteristics of the meat.     

Suitability of recombinant camel (Camelus dromedarius) chymosin as a coagulant for Cheddar cheese

Cheddar-type cheeses were manufactured using fermentation-produced camel or calf chymosin. There were no significant differences in the composition and pH between the cheeses made with either coagulant. The extent of primary proteolysis was significantly lower in cheeses made with camel chymosin than in cheeses made with calf chymosin. There were large quantitative differences between the peptide profiles of cheeses; however, the levels of amino acids were similar except for isoleucine, histidine and lysine. The cheeses made with camel chymosin were characterized by lower intensities of sulphur and brothy flavours and showed less bitter taste; however, the cheeses made with calf chymosin had greater breakdown of texture, higher smoothness and mouthcoating and were more cohesive and adhesive. The results of this study suggest that camel chymosin appears to be suitable for making Cheddar cheese with lower levels of proteolysis but with good flavour.     

Effect of starter cultures on properties of soft white cheese made from camel (Camelus dromedarius) milk

This experiment was conducted to investigate the effect of starter cultures on the physicochemical properties, texture, and consumer preferences of soft white cheese (SWC) made from camel (Camelus dromedarius) milk. The experiment was laid out in a completely randomized design with 5 treatments [starter cultures; i.e., 1 thermophilic (STI-12), 2 blended (RST-743 and XPL-2), and 2 mesophilic (R-707 and CHN-22) cultures]. Starter cultures STI-12 and RST-743 were inoculated at 37°C, whereas XPL-2, R-707, and CHN-22 were inoculated at 30°C. Camel milk inoculated using STI-12 and RST-743 cultures resulted in faster acidification than XPL-2, R-707, and CHN-22 cultures. Camel milk SWC made using STI-12 and CHN-22 cultures gave lower pH (4.54) and titratable acidity (0.59), respectively, whereas R-707 culture resulted in high cheese yield (13.44 g/100 g). In addition, high fat (20.91 g/100 g), protein (17.49 g/100 g), total solids (43.44 g/100 g), and ash (2.40 g/100 g) contents were recorded for SWC made from camel milk made using RST-743 culture. Instrumental analysis of cheese texture revealed differences in resistance to deformation in which camel milk SWC made using RST-743 culture gave higher firmness (3.20 N) and brittleness (3.12 N). However, no significant difference was observed among camel milk SWC adhesiveness made using different starter cultures. Consumer preference for appearance, aroma, taste, and overall acceptances of SWC were affected by inoculation of starter cultures. Considering curd firmness, cheese yield, compositional quality, and textures using STI-12, RST-743, and R-707, these cultures were found to be better for the manufacture of camel milk SWC.     

Angiotensin converting enzyme‐inhibitory activity and antimicrobial effect of fermented camel milk (Camelus dromedarius)

This study aimed to determine the angiotensin converting enzyme‐inhibitory activity and antimicrobial effect of fermented camel milk. Samples were prepared either using Lactobacillus acidophilus and Streptococcus thermophilus or Lactobacillus helveticus and Str. thermophilus and labelled as S1 and S2, respectively. The IC₅₀ values of S1 and S2 samples ranged between 113–200 and 70–133 μg/mL, respectively. The antimicrobial effects of S1 and S2 samples against Bacillus cereus, Salmonella Typhimurium and Staphylococcus aureus were apparent after 12 h of incubation and continued until 15 days of storage, whereas unfermented camel milk exhibited no antimicrobial effects against any of the tested pathogens.     

Alternative splicing of lactophorin mRNA from lactating mammary gland of the camel (Camelus dromedarius).

The objective of this study was to determine the corrected structure of lactophorin, a major whey protein in camel milk. The protein had 60.4% amino acid sequence identity to a proteose peptone component 3 protein from bovine whey and 30.3% identity to the glycosylation-dependent cell adhesion molecule 1 in mice. The N-terminal heterogeneity of the protein was a result of alternative mRNA splicing. About 75% of the protein was expressed as a long variant A with 137 amino acid residues and a molecular mass of 15.7 kDa; about 25% was as a short variant B with 122 amino acid residues and a molecular mass of 13.8 kDa. Both proteins are probably threefold phosphorylated. In contrast to the related proteins, no glycosylation was found in camel lactophorin. Because of this difference, specific interaction with carbohydrate binding proteins, as reported for the murine protein, can be excluded, and a function of the protein other than cell recognition or rotaviral inhibition is proposed. The concentration of lactophorin in camel milk was found to be about three times higher than the concentration of the bovine homologue in bovine milk. Pronounced similarities existed between the primary and secondary structures of bovine and camel proteins. We speculated that camel lactophorin has a similar function to that of bovine protein in milk, which is supposed to be the prevention of fat globule aggregation and the inhibition of spontaneous lipolysis by lipoprotein lipase.     

Effect of body fat distribution on the fatty acid composition of the depot fat of cattle

The influence of liveweight, total carcass fat and the amount of fat at five specific anatomical locations on the fatty acid composition of the depot fat of adult ruminants was examined. The total carcassfat and the amount offat at specific locations seem to affect the fatty acid composition significantly. No important significant correlation between liveweight and fatty acid composition was found. There was an increase in odd, even and branched chain fatty acids, and a decrease in linoleic acid, with increase in animal age.     

磷浓度对粉核油球藻Pinguiococcus pyrenoidosus CCMP2078生长和脂肪酸组成的影响

以粉核油球藻(Pinguiococcus pyrenoidosus CCMP2078)为实验材料,探讨了不同磷浓度对其生长、脂肪酸组成、EPA和PUFAs含量的影响。结果表明:在18~144μmol/L磷浓度范围内,P.pyrenoidosus CCMP2078的生长较好,当磷浓度为144μmol/L时,藻生长最快,细胞干重为0.11g/L;磷浓度为3.6μmol/L时,藻的生长受到明显抑制,细胞干重仅为磷浓度为36μmol/L时的一半,此时藻体的EPA和PUFAs含量均达最低值。在18~144μmol/L的磷浓度范围内,EPA和PUFAs含量随着磷浓度的升高呈下降趋势,当磷浓度为18μmol/L时,EPA和PUFAs含量均最高,分别占总脂肪酸的18.4%和33.57%。     

Lactoferrin and immunoglobulin contents in camel's milk (Camelus bactrianus, Camelus dromedarius, and Hybrids) from Kazakhstan

Lactoferrin (Lf) and IgG were estimated in camel's milk from Kazakhstan, where 2 species of camels (Camelus bactrianus, Camelus dromedarius) and their hybrids cohabit. The concentrations of Lf and IgG were determined according to 3 variation factors: region (n = 4), season (n = 4), and species (n = 5; sample 4 was mixed milk and sample 5 was of unknown origin). The mean values in raw camel's milk were 0.229 ± 0.135 mg/mL for Lf concentration and 0.718 ± 0.330 mg/mL for IgG concentration. The seasonal effect was the only significant variation factor observed, with the highest values in the spring for Lf and in the winter for IgG. The Lf concentration varied in 1-wk postpartum milk from 1.422 to 0.586 mg/mL. The range in IgG concentration was wide and decreased from 132 to 4.75 mg/mL throughout the 7 d postpartum, with an important drop after parturition. In fermented milk, the lactoproteins are generally hydrolyzed. For milk samples from undefined species, discriminant analyses did not allow the origin of the species to be determined. A slight correlation between Lf and IgG concentrations was observed in raw milk. The values were slightly higher than those reported in cow's milk, but this difference was insufficient to attribute medicinal virtues to camel's milk.     

Chemical characterization of the oligosaccharides in Bactrian camel (Camelus bactrianus) milk and colostrum

Bactrian camel milk and colostrum are commonly used as foods in Mongolia, whose people believe that these products promote human health. It has been hypothesized that milk oligosaccharides are biologically significant components of human milk, acting as receptor analogs that inhibit the attachment of pathogenic microorganisms to the colonic mucosa, and as prebiotics, which stimulate the growth of bifidobacteria within the infant colon. To evaluate their biological significance, we studied the oligosaccharides present in samples of Bactrian camel milk and colostrum. Using ¹H-nuclear magnetic resonance spectroscopy, we identified and characterized the following oligosaccharides of camel colostrum: Gal(β1–4)[Fuc(α1–3)]Glc (3-fucosyllactose), Gal(β1–3)Gal(β1–4)Glc (3′-galactosyllactose), Gal(β1–6)Gal(β1–4)Glc (6′-galactosyllactose), Neu5Ac(α2–3)Gal(β1–4)Glc (3′-sialyllactose), Neu5Ac(α2–6)Gal(β1–4)Glc (6′-sialyllactose), Neu5Ac(α2–3)Gal(β1–3)Gal(β1–4)Glc (sialyl-3′-galactosyllactose), Neu5Ac(α2–6)Gal(β1–4)GlcNAc(β1–3)Gal(β1–4)Glc (sialyllacto-N-tetraose c), Neu5Ac(α2–3)Gal(β1–3)[Gal(β1–4)GlcNAc(β1–6)]Gal(β1–4)Glc (sialyllacto-N-novopentaose a), Gal(β1–3)[Neu5Ac(α2–6)Gal(β1–4)GlcNAc(β1–6)]Gal(β1–4)Glc (sialyllacto-N-novopentaose b); and Neu5Ac(α2–6)Gal(β1–4)GlcNAc(β1–3)[Gal(β1–4)GlcNAc(β1–6)]Gal(β1–4)Glc (monosialyllacto-N-neohexaose). The oligosaccharides in the mature camel milk were characterized as 3′-galactosyllactose, Gal(β1–3)[Gal(β1–4)GlcNAc(β1–6)]Gal(β1–4)Glc (lacto-N-novopentaose I), and 3′-sialyllactose.