Comparative fatty acids composition and cholesterol content in Bactrian (Camelus bactrianus) and dromedary camel (Camelus dromedarius) meat.

The present study is aimed at comparing the fatty acid profiles, cholesterol, and atherogenicity index of Bactrian and dromedary camel meat by using discriminant analysis to identify the more discriminating fatty acids. Six muscles were sampled from nine Bactrian and nine dromedary camels and analyzed for fatty acid parameters and cholesterol content. The mean fatty acid profiles differed in higher proportion between species than between muscles. The main discriminating fatty acids between species (100% well-classed samples) were C15:0, C17:1, C14:1, C20:0, and C18:0. A significant difference was also observed in cholesterol content, with more cholesterol in Bactrian meat (53.6 ± 12.5 mg/100 g) compared to dromedary meat (49.4 ± 11.2 mg/100 g). However, the atherogenicity index was lower in Bactrian meat (1.196 ± 0.148) than in dromedary meat (1.379 ± 0.109). Despite the dietetic interest in camel meat due to its low cholesterol and low-fat content, the high atherogenicity index compared to other red meat appeared as an unfavorable argument.

Chemical composition, quality and histochemical characteristics of individual dromedary camel (Camelus dromedarius) muscles.

This study characterized the chemical composition, quality and histological traits of six muscles from 10 dromedary carcasses. There were significant differences in moisture, fat, protein, mineral, saturated and unsaturated fatty acid contents between muscles. The longissimus thoracis (LT) had the highest cooking loss (33.5%) and triceps brachii (TB) the lowest (29.2%). The shear force value of semitendinosus (ST), semimembranosus (SM) and biceps femoris (BF) were significantly higher than infraspinatus (IS), TB and LT. The LT had significantly higher values for L*, a*, b* than ST. The SM had the lowest MFI (65.3), while IS had the highest value (75.8). The ST significantly had the highest and lowest proportions of Type I and Type IIA muscle fibers, respectively than other muscles. This study indicated that composition, quality, and histochemical parameters varied among camel muscles and the knowledge of this variation allows for better marketing and processing of camel meat.

Disclosing the origin and diversity of Omani cattle.

Among all livestock species, cattle have a prominent status as they have contributed greatly to the economy, nutrition and culture from the beginning of farming societies until the present time. The origins and diversity of local cattle breeds have been widely assessed. However, there are still some regions for which very little of their local genetic resources is known. The present work aimed to estimate the genetic diversity and the origins of Omani cattle. Located in the south-eastern corner of the Arabian Peninsula, close to the Near East, East Africa and the Indian subcontinent, the Sultanate of Oman occupies a key position, which may enable understanding cattle dispersal around the Indian Ocean. To disclose the origin of this cattle population, we used a set of 11 polymorphic microsatellites and 113 samples representing the European, African and Indian ancestry to compare with cattle from Oman. This study found a very heterogenic population with a markedly Bos indicus ancestry and with some degree of admixture with Bos taurus of African and Near East origin.

Effects of electrical stimulation on histochemical muscle fiber staining, quality, and composition of camel and cattle Longissimus thoracis muscles.

The effects of electrical stimulation on muscle fiber type, meat quality, and composition of Longissimus thoracis muscles from one-humped camels and Dofari Omani cattle of a comparable age range were investigated. A low-voltage electrical stimulation with 90 V, 14 Hz (pulse of 7.5-millisecond duration every 70 milliseconds) 20 min postmortem was applied. Samples from the left muscle were collected from 20 (2 to 3 y) camels and 24 cattle (1 to 3 y). For chemical composition, muscle samples were dried in a freeze dryer, and then ground to determine moisture, protein, fat, and ash. Macro- and micro-minerals were determined using an Inductively Coupled Plasma Emission Spectrometer. Quality characteristics of the meat were evaluated using shear force value, pH, sarcomere, myofibrillar fragmentation index, expressed juice, cooking loss percent, and CIE L*, a*, b* color values. Electrical stimulation resulted in a significantly (P < 0.05) more rapid pH fall in the muscle during the first 24 h after slaughter in both species. Muscles from electrically stimulated carcasses had significantly (P < 0.05) lower ultimate pH, longer sarcomere, and lower shear force values than those from nonstimulated carcasses. Lightness (L*), myofibrillar fragmentation, and expressed juice were significantly (P < 0.05) higher for stimulated than for nonstimulated muscles. Muscles of camels had significantly (P < 0.05) higher expressed juice, cooking loss percent, redness color (a*), and lower fat, Mg, K, and P than those from cattle. Electrical stimulation improved quality characteristics of meat from both species. This indicates that meat quality of local camel and cattle can be improved by electrical stimulation and consequently improves their acceptability to consumers and better marketability.

Effect of low voltage electrical stimulation on biochemical and quality characteristics of Longissimus thoracis muscle from one-humped Camel (Camelus dromedaries).

The effects of electrical stimulation (90V) 20min post mortem on meat quality and muscle fibre types of four age group camels (1-3, 4-6, 7-9, 10-12 years) camels were assessed. Quality of the Longissimus thoracis at 1 and 7 days post mortem ageing was evaluated using shear force, pH, sarcomere length, myofibrillar fragmentation index, expressed juice, cooking loss and L(∗), a(∗), b(∗) colour values. Age of camel and electrical stimulation had a significant effect on meat quality of L. thoracis. Electrical stimulation resulted in a significantly (P<0.05) more rapid pH fall in muscle during the first 24h after slaughter. Muscles from electrically-stimulated carcasses had significantly (P<0.05) lower pH values, longer sarcomeres, lower shear force value, higher expressed juice and myofibrillar fragmentation index than those from non-stimulated ones. Electrically-stimulated meat was significantly (P<0.05) lighter in colour than non-stimulated based on L(∗) value. Muscles of 1-3 year camels had a significantly (P<0.05) lower shear force value, and pH, but longer sarcomere, and higher myofibrillar fragmentation index, expressed juice, and lightness colour (L(∗)) than those of the 10-12 years camels. The proportions of Type I, Type IIA and Type IIB were 25.0, 41.1 and 33.6%, respectively were found in camel meat. Muscle samples from 1-3 year camels had significantly (P<0.05) higher Type I and lower Type IIB fibres compared to those from 10-12 year camel samples. These results indicated that age and ES had a significant effect on camel meat quality.

The influence of seasonal temperatures on meat quality characteristics of hot-boned, m. psoas major and minor, from goats and sheep.

Samples of psoas major and minor muscles were randomly collected weekly from 203 (99 hot and 104 cool seasons) Omani goats, 215 (106 hot and 109 cool seasons) Omani sheep, 212 (104 hot and 108 cool seasons) Somali goats, 242 (127 hot and 115 cool seasons) Somali sheep and 211 (110 hot and 101 cool seasons) Australian Merino sheep slaughtered at the Central Slaughterhouse in Oman to investigate the effect of season on meat quality. The collection period was during November 2004-October 2005 and divided into two seasons according to ambient temperatures and relative humidity. These were termed: cool season (average temperature of 21°C and 59% relative humidity and hot season (average temperature of 35°C and 47% relative humidity). Muscles collected during the hot season had significantly (P<0.05) higher ultimate pH values (5.78) than those collected during the cool season (5.65). Myofibrillar fragmentation index was significantly (P<0.05) higher for hot season samples (86.88%) than for cool season samples (85.59%). Expressed juice was significantly (P<0.05) higher for cool season samples (36.84) than for hot season samples (35.74). Goat meat from the hot seasonal group was significantly (P<0.05) darker than the cold season group based on L∗ (37.6 vs. 39.6), a∗ (20.0 vs. 23.3) and b∗ (3.6 vs. 4.2) colour measurements. These results indicated that high ambient temperatures had caused an increase in muscle ultimate pH leading to significant effects on meat quality.

A review of the growth, and of the carcass and meat quality characteristics of the one-humped camel (Camelus dromedaries).

The dromedary camel is a good source of meat especially in areas where the climate adversely affects the performance of other meat animals. This is because of its unique physiological characteristics, including a great tolerance to high temperatures, solar radiation, water scarcity, rough topography and poor vegetation. The average birth weight of camels is about 35kg, but it varies widely between regions, breeds and within the same breed. The meat producing ability of camels is limited by modest growth rates (500g/day). However, camels are mostly produced under traditional extensive systems on poor levels of nutrition and are mostly slaughtered at older ages after a career in work, racing or milk production. Camels reach live weights of about 650kg at 7-8 years of age, and produce carcass weights ranging from 125 to 400kg with dressing-out percentage values from 55% to 70%. Camel carcasses contain about 57% muscle, 26% bone and 17% fat with fore halves (cranial to rib 13) significantly heavier than the hind halves. Camel lean meat contains about 78% water, 19% protein, 3% fat, and 1.2% ash with a small amount of intramuscular fat, which renders it a healthy food for humans. Camel meat has been described as raspberry red to dark brown in colour and the fat of the camel meat is white. Camel meat is similar in taste and texture to beef. The amino acid and mineral contents of camel meat are often higher than beef, probably due to lower intramuscular fat levels. Recently, camel meat has been processed into burgers, patties, sausages and shawarma to add value. Future research efforts need to focus on exploiting the potential of the camel as a source of meat through multidisplinary research into efficient production systems, and improved meat technology and marketing.

The effect of date fibre supplemented with an exogenous enzyme on the performance and meat quality of broiler chickens.

1. Two experiments were conducted to evaluate the use of date fibre as a partial replacement of maize as a source of energy for growing broiler chicken. In experiment 1, date fibre was given alone to determine apparent metabolisable energy (AME) and apparent ileal digestibility of amino acids and crude fibre. 2. Date fibre had lower AME content (8.7 vs 13.6 MJ/kg) and apparent ileal digestibility coefficients for dry matter (0.35 vs 0.83), crude fibre (0.20 vs 0.54) and amino acids. 3. Based on the results of experiment 1, a growth study was conducted to test the effect of exogenous enzymes on the nutritive value of date fibre (experiment 2). 4. Three date fibre contents (5, 10 and 15%) with and without enzyme supplementation were evaluated. Daily feed intake, body weight gain and feed conversion ratio were measured. At the end of experiment 2, 160 birds were randomly selected and slaughtered to evaluate carcase and meat quality traits as well as measuring ileal viscosity. 5. Substitution of maize by 10 and 15% date fibre significantly depressed AME. Enzyme supplementation did not improve crude fibre digestibility. The inclusion of date fibre in the diets except at 5% decreased average daily gains, feed intake and feed conversion ratio. 6. Addition of date fibre caused a significant increase in the weights of total digestive tract, pancreas and caecum. Addition of date fibre or the exogenous enzyme had no significant effect on carcase or meat quality characteristics. 7. Date fibre increased ileal digesta viscosity compared to the control. Addition of the exogenous enzyme decreased the viscosity of the basal diets but had no effect on the date fibre diets.8. This study indicated that date fibre can be included at levels of 5% in broiler diets without affecting performance.

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 48h. 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 0.141mg/100g 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.

Effects of transportation at high ambient temperatures on physiological responses, carcass and meat quality characteristics of three breeds of Omani goats.

The experiment was designed to determine the effects of short road transportation in an open truck during the hot season on live weight shrink, physiological responses, carcass, and meat quality characteristics in three breeds of Omani goats. Forty-two male goats (12months of age) representing equally three breeds of Omani goats (Batina, Dhofari, and Jabal Akhdar) were divided into two groups: 2h transportation stress (TS) or not transported (NT). The NT group remained unstressed in holding pens with feed and water provided ad libitum prior to slaughter, while the TS group was transported on the day of slaughter 100km in an open truck. The average temperature during transportation was 37°C. All animals were blood-sampled before loading and prior to slaughter via jugular venipuncture. Animals were weighed just before loading onto a truck and after transport to assess shrinkage. Muscle shear force, sarcomere length, pH, expressed juice, color, and cooking loss were measured on samples from Mm longissimus dorsi (LD), biceps femoris (BF), and semitendinosus (ST) muscles collected at 24h postmortem at 1-3°C. Live weight shrinkage losses were between 1.07 and 1.28kg. The TS goats had higher plasma cortisol (P<0.01), adrenaline, nor-adrenaline, and dopamine concentrations (P<0.05) than NS goats. Blood serum from Batina goats had significantly (P<0.05) higher cortisol, adrenaline and dopamine and nor-adrenaline concentrations than those from Jabal Akdhar goats. Transportation stress had a significant (P<0.05) effect on meat quality characteristics of the LD, BF, and ST muscles. Meat from TS goats had significantly higher ultimate pH, expressed juice, cooking loss percentage, shear force, but significantly lower sarcomere length, L(∗), a(∗), and b(∗) values. LD muscles of Batina goats had significantly higher ultimate pH values and lower L(∗) values than Dhofari and Jabal Akdhar goats. These results indicated that subjecting goats to the 2-hour road transportation with high ambient temperatures can generate major physiological and muscle metabolism responses.

The effects of replacing Rhodes grass (Chloris gayana) hay with ghaf (Prosopis cineraria) pods on the performance of Omani native sheep.

A feeding trial using various levels of dry pods of ghaf (Prosopis cineraria) was carried out with 28 Omani native male sheep. Individual feed intake and body weight were determined for 50 days to allow assessment of the effects of the feeds on growth, feed intake, feed conversion and carcase measurements. The ripened ghaf pods contained 91% dry matter (DM), 13.5% crude protein (CP), 14.3% crude fibre (CF), 1.3% ether extract (EE) and 5.2% ash (on DM basis). Four levels of ghaf (0, 15%, 30% and 45%) were used with corresponding decreasing proportions of Rhodes grass (RGH) hay. Animals fed rations containing RGH as the sole source of roughage and no ghaf grew faster (135 g/day) and had better feed conversion than those fed various levels of ghaf. Sheep fed 15% ghaf gained reasonably well (90 g/day) and had carcase attributes similar to those fed no ghaf. Sheep fed 30% ghaf still gained weight but those fed 45% ghaf lost weight. Negative effects on growth appeared to occur after 6 weeks of feeding ghaf.

The influence of season on quality characteristics of hot-boned beef m. longissimus thoracis.

Samples of m. longissimus thoracis (LT) muscle were randomly collected from 70 Omani beef cattle 1 h after slaughter between August 2001 and July 2002 in the Muscat Municipality central slaughterhouse to investigate the effect of seasonal parameters on meat quality during the hot and cool seasons of Oman. The collection period (12 months) was divided into two seasons according to ambient temperatures and relative humidity and termed: Cool Season (November-March with average temperature of 21.2±1.40 °C and 57.9±1.61% relative humidity) and Hot Season (April-October with average temperature of 34.3±1.67 °C and 48.8±7.57% relative humidity). The season had a significant effect on meat quality characteristics of the LT muscle. Muscles collected during the hot season had significantly (P<0.001) higher ultimate pH values (6.24) with significantly (P<0.001) lower Warner-Bratzler (WB) shear force values (10.12) than those collected during the cool season (5.54 and 15.58). In these hot-boned samples, there was a linear relationship between ultimate pH and WB shear values. Cooking loss was significantly (P<0.001) higher for cool season samples (26.01%) than from hot season samples (19.75%). Beef from the hot season group had significantly (P<0.001) darker meat than that of the cold season group, based on L* (31.45 vs 35.58), a* (18.53 vs 23.19) and b* (4.16 vs 6.40) colour measurements. There was a linear relationship between ultimate pH and cooking loss, L*, a* and b*. These results indicated that heat stress (>30 °C) lead to physiological stress in beef cattle, which in turn increased muscle ultimate pH and influenced related meat quality characteristics.

Comparative effect of low levels of dietary cobalt and parenteral injection of vitamin B(12) on carcass and meat quality characteristics in Omani goats.

The effect of low levels of dietary cobalt (Co) on carcass and meat quality characteristics were investigated in 36 male goats of three different Omani breeds namely Batina, Dhofari and Jabal Akdhar. Goats were randomly divided into two groups at 10 weeks of age, control (18 animals) and treated (18 animals). Goats from both groups were fed Rhodesgrass hay and a commercially prepared diet containing 0.10 and 0.12 mg Co/kg DM, respectively from 10 to 46 weeks of age. Animals in the treated group were supplemented with subcutaneous injections of 2000 µg of hydroxocobalamin (vitamin B(12)) on week 10 and thereafter for 46 weeks at 8-week intervals. At 46 weeks of age, the animals were slaughtered and their carcass and meat quality characteristics compared. Serum vitamin B(12) levels were significantly higher in goats from the treated group from week 16 till the end of the experiment. The final live and carcass weights were significantly higher (P<0.05) for the treated Batina group by 13.4 and 8.3% compared with the control group, respectively. Shoulder, rack, loin and leg cut weights were also significantly higher (P<0.05) for the Batina treated group compared with the control group by 14.7, 16.8, 12.8 and 13.1%, respectively. Carcass length, leg length, width behind shoulder, maximum shoulder width and longissimus muscle area were significantly higher (P<0.05) for the Batina treated breed than for the control group by 6.7, 5.8, 10.1, 10.1 and 28.5%, respectively. Four muscles (Mm. longissimus dorsi, biceps femoris, semimembranosus, and semitendinosus) from treated and control groups were evaluated for ultimate pH, expressed juice, cooking loss%, colour (L*, a* and b*), and Warner-Bratzler shear force values. There were significant treatment effects on these muscle quality characteristics for the Batina breed only. Muscles from the treated group showed significantly lower (P<0.05) shear force values of between 15 and 27% than those from the control group. Moreover, the treated Batina goats tended to have significantly lower (P<0.05) ultimate pH, expressed juice, L* and higher a* values than those from the control group for longissimus dorsi and biceps femoris muscles only.

Effects of body weight and sex on carcass tissue distribution in goats.

Distribution of fat, muscle and bone tissues was studied in bucks, wethers and doe Jebel Akhdar (JA) Omani goats raised under intensive management and slaughtered at 11, 18 or 28 kg body weight (BW). Weight of individual tissues was expressed as percentage of total respective tissue weight in the half carcass. Weight of total body fat in the empty body weight (EBW) ranged between 7.6% in bucks at 11 kg BW and 23.5% in does at 28 kg BW. At 18 kg BW, JA goats had higher TBF, carcass and non-carcass fat than those slaughtered at 12 kg BW (P<0.001). Does and wethers had a faster rate of deposition of carcass and non-carcass fat relative to EBW. Therefore, they had higher fat content (P<0.001) than bucks at 28 kg BW. The highest proportion of fat in the body was deposited intermusculary whereas the omentum constituted the highest non-carcass fat proportion. About 55% of the musculature in JA goat carcasses was found in muscle groups of the proximal hind leg, around the vertebral column and in the proximal forelimb (expensive muscle groups). Bucks had higher proportions of musculature in the forequarter (P<0.001) and intrinsic muscles of the neck but lower proportions of muscles at the proximal hind limb (P<0.001) than does and wethers. About 51% of the total skeleton was found in the axial skeleton, 22-23% in the forelimb and 22-23% in the hind limb of JA goats. There were few sex or slaughter weight effects on proportions of bone weight in the skeleton. In general, slaughter weight and sex effects on tissue distribution were more pronounced in the fat tissue. The magnitude of these effects on muscle and bone tissues was small and is unlikely to have economic impact on meat production from goats.

An evaluation of the growth, carcass and meat quality characteristics of Omani goat breeds.

Body weight, growth, carcass and meat quality characteristics were evaluated in three breeds of goats (Batina, Dhofari and Jabal Akdhar) in Oman. Fourteen intact male goats from each breed were used. Jabal Akdhar goats had significantly heavier slaughter, empty body, and carcass weights and higher growth rates than Dhofari and Batina goats. Jabal Akdhar goats had significantly heavier internal organs than the other two breeds. Dressing-out percent (based on empty body weight) of goats ranged between 53 and 57%, with the Dhofari goats having the highest value. Longissimus muscle dimensions varied between the three breeds, with Jabal Akdhar having a significantly larger area than Batina with Dhofari in between. Dhofari goats produced significantly shorter and wider carcasses than Batina and Jabal Akhdar goats. Carcass cuts were significantly heavier in Jabal Akdhar than the other two breeds. Four muscles (Mm. longissimus dorsi, biceps femoris, semitendinosus, and semimembranosus) from both sides of each carcass were subjected to two different ageing periods (1 day vs. 6 day) and evaluated for ultimate pH, expressed juice, percent cooking loss, colour (L*, a* and b*), and Warner-Bratzler shear force. Breed had a significant influence on pH and percent cooking loss but not on expressed juice, shear force value and colour (CIE L*,a*, b* values). Muscles from the Batina goats had significantly higher ultimate pH values and lower percent cooking loss than Dhofari and Jabal Akdhar goats. Ageing from 1 to 6 days increased tenderness significantly (27%), but decreased cooking loss by 5%.

Ileal amino acid digestibility assay for the growing meat chicken--comparison of ileal and excreta amino acid digestibility in the chicken.

1. The apparent and true amino acid digestibilities in sorghum, wheat, soyabean meal, meat-and-bone meal, fish meal and blood meal for growing meat chickens were determined using an assay based on the collection of digesta from the terminal ileum and comparison was made with digestibility values determined using an excreta-based assay. 2. Five-week-old meat chickens were given maize-soyabean meal basal diet or mixtures of the basal diet and test diets containing the 6 ingredients as the sole source of dietary protein (50:50 on weight basis). Apparent amino acid digestibility values of assay diets at ileal and excreta levels were calculated using chromic oxide as the indigestible marker. True digestibility values were calculated using endogenous outputs determined by feeding a protein-free diet. Amino acid digestibilities of the ingredients were calculated by difference. 3. The site of measurement had no influence on endogenous amino acid output, the exceptions being aspartic acid and glutamic acid. The output of these two amino acids was higher in the excreta. 4. Significant differences were found between ileal and excreta-based digestibility of certain amino acids in some ingredients, with excreta values being usually higher than the ileal values, indicating a net catabolism of amino acids in the large intestine. The degree of net amino acid disappearance was found to be variable among amino acids and ingredients. In general, threonine had the lowest digestibility at the ileal level and, compared with other amino acids, the highest degredation during passage through the hindgut. 5. The results showed that digestibility determination based on excreta collection will overestimate the uptake for some amino acids in some feeds. The degree of overestimation was often considerable, ranging from 8.9% (apparent digestibility of threonine in soyabean meal) to 56% (apparent digestibility of aspartic acid in wheat). It is concluded that digestibility values measured at the terminal ileum provide a more reliable measure of amino acid availability than those measured in the excreta.

Effects of age on fatty acid composition of the hump and abdomen depot fats of the Arabian camel (Camelus dromedarius).

This study aimed to quantify concentrations of fatty acids in the hump and abdomen fats of three different age groups of camel. Hump and abdomen fats were extracted from eight each of one-humped camels (Camelus dromedarius) of three age groups: group 1 (<1 year old), group 2 (1-3 years old) and group 3 (>3 years old). The fatty acid methyl ester concentrations of these fats were determined by gas-liquid chromatography (GLC). The percentage of fat in the hump (H) and abdomen (A) fats was significantly (P<0.05) lower for group 1 (H 92.0% and A 94.3%) than for group 2 (H 97.4% and A 97.2%) and group 3 (H 97.6% and A 97.5%), on a dry matter basis. Hump and abdomen fats from the three different groups had similar fatty acid patterns with more saturated than unsaturated fatty acids. The saturated fatty acids in the hump fats accounted for 58.3, 67.6, and 63.0% of the total fatty acids for groups 1, 2 and 3, respectively; group 1 had significantly (P<0.05) lower saturated and higher unsaturated fatty acid concentrations than group 2. The iodine numbers were significantly (P<0.05) higher in group 1 than either group 2 or 3. Palmitic acid (C16:0) was the major fatty acid in hump fat with 32.06, 32.90 and 34.37%, followed by oleic acid (C18:1) 33.65, 21.66 and 28.91.0% and stearic acid (C18:0) 18.85, 24.13 and 20.74% for groups 1, 2 and 3, respectively. Group 1 had significantly higher (P<0.05) oleic acid and lower stearic acid concentrations than group 2. The melting point of both hump and abdomen fats varied between the age groups. This study indicated that age has an effect on the fatty acid composition and the melting point of hump and abdomen fats in one-humped Arabian camels.

Ileal amino acid digestibility assay for the growing meat chicken--effect of the imposition of a fasting period and the nature of the test diet.

1. The objective of this study was to investigate the effects of cold-pelleting, the length of the fasting period before feeding of the test diet and the nature of the test diet on apparent ileal nitrogen (N) digestibility in the broiler chicken. 2. Four-week-old broiler chickens were given a pelleted or non-pelleted maize/soyabean meal (basal) diet. The birds were starved for 24 h, given a single test meal (25 g) by intubation and killed 4 h after the start of feeding by administration of a barbiturate, to allow sampling of ileal digesta (terminal 15 cm). Cold-pelleting did not affect apparent ileal N digestibility. 3. Four-week-old broiler chickens were fasted for 12 or 24 h and then received a test meal (1 h free access) of either a pelleted soyabean meal or a pelleted meat-and-bone meal diet or were continuously fed on one of the two diets. The imposition of a fast did not affect apparent ileal N digestibility. However, a 24 h fasting procedure was preferred, as the between animal variation for apparent ileal N digestibility was lower than for the 12 h fast or for continuous feeding. 4. Four-week-old broiler chickens were given either semi-synthetic starch-based diets containing maize, wheat bran, meat-and-bone meal or fish meal as the sole sources of protein or each of these diets in combination with the basal diet (50:50 on a dry matter basis). With the exception of the maize diet, the apparent ileal N digestibility values calculated by correcting for the digestibility of the basal dietary component were significantly lower than when digestibility was determined directly using a diet in which the respective proteins were the sole protein source. This implies that interactions between the dietary ingredients influence estimates of apparent ileal N digestibility.

Development of an ileal amino acid digestibility assay for the growing chicken--effects of time after feeding and site of sampling.

1. The study aimed to establish the optimum time after ingestion and optimum sampling site for the development of an ileal amino acid digestibility assay for broiler chickens. 2. To establish the optimal sampling time, 4-week-old broiler chickens were given one of 6 protein sources (meat-and-bone, soyabean, cottonseed, fish, maize and wheat meals) as the sole source of protein in a test diet. The diets contained chromic oxide as an indigestible marker. The birds were starved for 24 h, fed and subsequently killed for sampling of ileal digesta (terminal 15 cm) at 2, 3, 4, 5 and 6 h after the start of feeding. 3. For the soyabean, fish, wheat and maize meal diets, sampling time had no significant effect on apparent ileal nitrogen digestibility, whereas for the meat-and-bone and cottonseed meal diets there was a significant quadratic effect of sampling time. The amount of digesta collected was maximised and the mean apparent ileal nitrogen digestibility had the lowest variation around the 4 h sampling time. 4. To establish the optimum sampling site, 4-week-old chickens were given either a meat-and-bone, a soyabean or a wheat bran meal-based diet. The birds were killed 4 h after the start of feeding, and digesta were sampled from 0-10, 0-15, 0-20 or 0-25 cm of terminal ileum. 5. There was no significant effect of sampling site on the apparent ileal digestibility of dietary nitrogen. The terminal 15 cm of ileum was considered a preferred site for sampling ileal digesta from broiler chickens.

Manipulation of adult body composition by treatment of the neonatal rat with growth hormone and prolactin.

Previous studies involving fetal decapitation or hypophysectomy, and the treatment of neonates with hormones or antibodies, have suggested that changes in pituitary hormone status during the perinatal period may influence later body composition. In the present study, rats were treated for the first 21 days of life with twice daily subcutaneous injections of saline, recombinant bovine growth hormone (bGH) or pituitary ovine prolactin (oPRL). The bGH and oPRL were administered at doses of 0.2 or 0.4 microgram/g bodyweight/day. One-third of the rats in each treatment group were slaughtered at each of days 21, 60 and 120 of life and measurements made of: length and weight of the body; weights of bones and muscle groups in the hindlimb; weights of four fat depots (120-day group only); and the content of nitrogen (N) and fat in the carcass. bGH, but not oPRL, treatment increased weight of the femur and humerus (across ages) but neither treatment had marked effects on weights of muscle groups, carcass weight or carcass N content at any age. Both bGH and oPRL treatment significantly reduced weight of the subcutaneous scapular fat depot and reduced carcass fat content, but only in animals aged 120 days (i.e. 99 days after the cessation of treatment). It is concluded that treatment of rats with bGH and oPRL during the immediate postnatal period specifically retards the ability of animals to deposit body fat in later life by mechanisms which differ from those involved in the classical lipolytic/antilipogenic effects of bGH.