Role of Insoluble Fiber on Gizzard Activity in Layers

Effect of access to wood shavings on gizzard activity was examined for birds fed pelleted wheat and oat diets with or without whole cereal inclusion. Layers on litter floor fed wheat diets with access to coarse wood shavings showed up to 60% higher weight of the gizzard and its content than caged layers fed the same diets without access to wood shavings. No such effect was found by feeding oat diets. Thus, a significant interaction was found, indicating that the appetite for wood shavings may be dependent of fiber level of the diet. Appetite for wood shavings and paper was examined for birds fed wheat and oat diets in 2 other experiments. The intake of wood shavings and paper by birds fed a wheat-based diet was numerically twice as high as in birds fed an oat-based diet. However, the individual variation was remarkably high. Neutral detergent fiber (NDF) concentration in the gizzard of birds fed the oat diet was up to twice (P < 0.05) the fiber concentration in the gizzard of birds fed the wheat diet. Passage of structural fibers through the gizzard and the appetite for feathers in the absence of structural fibers were also studied in an experiment using diets based on rice and casein. Coarse fiber structures were observed to accumulate in the gizzard. In the absence of fiber, birds ate feathers, indicating that birds may eat feathers to compensate for the lack of structural components in the feed.     

Effect of dietary administration of oil extracts from rosemary and sage on lipid oxidation in broiler meat

1. Oxidation of meat and membrane from broilers fed on a diet containing 500 mg/kg rosemary and sage extracts was compared to meat and membrane oxidation from broilers receiving a control diet (not enriched with antioxidants) and a diet enriched in alpha-tocopheryl acetate (200 mg/kg). 2. After 9 d of refrigerated storage, thiobarbituric acid reactive substances of white meat from broilers fed on the control and the alpha-tocopheryl acetate-enriched diets were 0.51 and 0.25 mg malonaldehyde/kg meat, respectively. Values for meat from broilers fed on the diets containing the rosemary and sage extracts were in the range 0.30 to 0.35 mg malonaldehyde/kg meat, significantly lower than those from birds fed on the control diet. A similar trend was observed in the dark meat but differences were not significant at 9 d of storage. Similar trends were observed in raw samples stored at- 20C for up to 4 months and in samples cooked at 70C and kept stored under refrigeration for up to 4 d. 3. The meat from broilers fed on the diet containing spice extracts had smaller concentrations of total cholesterol oxidation products (COPS) than meat from the control group (P<0.05). Supplemental alpha-tocopheryl acetate reduced the COPS concentrations to a greater extent than did spice extracts (P<0.05). 4. A similar trend was observed in microsomal fraction isolates, in which the rate of metmyoglobin/hydrogen peroxide-catalysed lipid peroxidation was lower in animals receiving spice extracts than in those fed on the basal diet.     

Bill impaction in a group of captive Caribbean flamingos (Phoenicopterus ruber ruber).

Flamingos are filter feeders that only rarely ingest larger food items. Their bill anatomy is adapted to the suction, filtration, and ejection of a fluid medium. This case report documents a rare case of bill impaction in a group of Caribbean flamingos (Phoenicopterus ruber) that were kept in a mixed exhibit together with roseate spoonbills (Platalea ajaja) and scarlet ibis (Eudocimus ruber). The latter species received fatty minced meat as part of their diet, which was also accessible to the flamingos. Weakness and poor body condition of one flamingo were noted. On clinical examination, the animal was emaciated, hypoglycemic, and showed a severe impaction of the bill with a mixture of lard, mud, and sand. This mixture had compressed the tongue and eventually had most likely prevented further food intake. In five additional flamingos, a bulging of the gular area, similar to the extension of this area during the tongue-retraction stage of the feeding cycle, was noted and interpreted as a sign of tongue displacement by similar masses in their bills. All animals were caught and the masses removed. All animals resumed food intake immediately, and the emaciated animal rapidly improved in condition. Food presentation was changed so that the trays for the other species were no longer accessible to the flamingos, and no similar problems have been observed since that time.     

Does the length of time dried distillers' grain with solubles substitution for soybean meal affect physiological indicators and meat quality in finishing lambs?

This study examined how inclusion of dried distillers' grains with solubles (DDGS) in finishing lamb diets for different periods affects some physiological indicators and meat quality. A total of 40 male lambs were divided into four groups according to feeding regimen during the 120-day finishing period as follows: C120: no DDGS included in diet for 120 days; D120: DDGS included in diet for 120 days; D75: no DDGS included in diet for 45 days + DDGS included in diet for 75 days; D45: no DDGS included in diet for 75 days + DDGS included in diet for 45 days. Dietary inclusion rate of DDGS was 27.5%. Fattening performance and rumen parameters were not affected by treatment. Feeding regimens had no significant effect on meat quality except the instrumental tenderness and juiciness score. DDGS fed lambs had higher level of total trans fatty acids and n-6/n-3 ratio in meat. 10t-C18:1, 11t-C18:1 and 9c,11t conjugated linoleic acid contents of adipose tissue were higher in all the DDGS groups compared with C120 lambs (p < .001). These results suggest that soybean meal can be replaced with corn DDGS in lamb diets for up to 120 days during the finishing period with no adverse effects on some physiological response feedlot performance and meat quality.     

Anatomical and surface ultrastructural investigation of the tongue in the straw-coloured fruit bat (Eidolon helvum,Kerr 1972)

The morphology of tongue in straw-coloured fruit bat from tropical forests was evaluated in relation to frugivorous diets and in comparison with other species that consumes other food types. Gross, stereomicroscopy, scanning electron microscope and histological methods were used. The tongue was relatively long with round tip, which closely fitted into oral cavity. Five types of mechanical papillae included crown-like and trifid filiform papillae. Also bulky, cone-shaped papillae and long conical papillae were identified. These mechanical types also showed variations in shape, size and number of processes of papillae. Transitional forms of these mechanical papillae were present. Fungiform papillae with taste pores were interposed amongst filiform types in apex and body; three ovoid-shaped vallate papillae were in triangular arrangement on root and displayed taste pores. Some bulky, cone-shaped papillae surrounded the vallate papillae. Histologically, mechanical filiform types showed highly keratinized stratified squamous epithelium and dense connective tissue core with secondary papillae. Taste buds appeared in fungiform and vallate papillae. Neutral and acidic secretions were identified in lingual glands of root. The presence of prominent filamentous processes of filiform papillae and conical papillae of the tongue in conjunction with gustatory papillae ensures adaptation to copious fruit diets. The gross morphometric and histometric parameters of the tongue did not differ remarkably from previous values obtained for some fruit bats with comparable weight. This investigation showed similarities with fruit bats such as large flying fox and Egyptian fruit bat and reflect common diet and feeding habits but varied from insectivorous and nectivorous bats.     

竹酢粉对育肥猪肉品质和风味的影响

本试验旨在研究竹酢粉对育肥猪肉品质和风味的影响。试验选择40头体重相近育肥猪,随机分成5组(每组4个重复,每个重复2头)。对照组(CON)饲喂基础饲粮,抗生素组(ANT)饲喂基础饲粮+0.12%复合抗生素,竹酢粉组分别饲喂基础饲粮+0.5%(BV5)、1.0%(BV10)和1.5%(BV15)的竹酢粉,试验期60 d。结果表明:1)BV5和BV10猪肉红度值显著高于CON和ANT(P0.05),BV10和BV15猪肉剪切力显著低于CON(P0.05),各竹酢粉组猪肉剪切力均显著低于ANT(P0.05);2)BV10和BV15猪肉中天冬氨酸和风味氨基酸含量显著高于CON和ANT(P0.05),各竹酢粉组猪肉中谷氨酸含量均显著高于CON和ANT(P0.05);3)BV5和BV10猪肉中肌苷酸含量显著高于CON和ANT(P0.05),BV15猪肉中肌苷酸含量显著高于ANT(P0.05);4)BV10猪肉中棕榈酸和BV5猪肉中棕榈油酸含量显著高于其他各组(P0.05),BV10和BV15猪肉中十八烷烯酸含量显著高于CON(P0.05)。综上,竹酢粉可改善育肥猪肉品质,提高猪肉风味和营养价值,效果优于抗生素,建议添加量为1.0%。     

The Lingual Dorsal Surface of the Blue-Tongue Skink (Tiliqua scincoides)

The blue-tongue lizard ( Tiliqua scincoides ) is a variety of large skink common throughout Australia. There are seven species of Tiliqua and all of them have long bodies, short limbs and short and robust tails. T. scincoides occurs in a wide range of habitats; its diet is omnivorous. When threatened, it opens the mouth and protrudes its characteristic large fleshy cobalt blue tongue. It is currently found as a popular species and also as a pet animal in the European countries. No data are available in literature about the morphology of the tongue of T. scincoides ; therefore, the aim of the present study was to investigate by means of scanning electron microscopy and light microscopy, the anatomy of the dorsal lingual surface. Our results demonstrate the presence of a tongue tip with a smooth surface without papillae. The foretongue was characterized by a stratified epithelium with foliate-like papillae and deep inter-papillar spaces in the middle part and cylindrical papillae with a flat surface in the lateral parts. All the posterior area of the tongue was characterized by more compacted papillae and the inter-papillar spaces were very narrow. Light microscopy showed the presence of melanin throughout the tongue. No taste buds were recognized on the lingual dorsal surface. Therefore, the papillae probably have a mechanical function showing an important role in the swallowing phase. The morphology of the tongue surface can be correlated to the diet and, different roles, as in other examined species, can be hypothesized for different areas.     

Quality of different bedding materials and their influence on the compostability of horse manure

The air quality of the stable and management and composting of manure can be improved by choosing bedding material with certain desirable properties. The optimal bedding material doesn't cause hygiene problems in the stable. It absorbs ammonia, is economic in use, and decomposes quickly with manure. The objective of this trial was to compare both quality of different bedding materials and their influence on the composting process of horse manure. Bedding materials used in the study were wood chips, straw, peat, hemp, linen, sawdust, shredded newspaper and the mixtures, peat/wood chips, peat/sawdust, and peat/straw. Peat and peat mixtures had the best quality of ammonia absorption, water holding, and manure fertilization value. The number of fungi and bacteria were lower in shredded newspaper and wooden materials than in straw, linen, hemp, and peat. The composting temperature became high enough for at least a partial destruction of parasites and seeds within the rubbish heaps in all boxes. Only peat manure was ready for further plant production after one month's composting period. Other bedding materials were decomposed only partially or not at all during the study.     

Evaluation of a digestion assay and determination of sample size and tissue for the reliable detection of Trichinella larvae in walrus meat.

A digestion assay was validated for the detection of Trichinella larvae in walrus (Odobenus rosmarus) meat, and appropriate samples for testing were determined using tissues from infected walruses harvested for food. Examination of muscles from 3 walruses showed that the tongue consistently contained approximately 2-6 times more larvae than the pectoral and intercostal muscles. Comparison of numbers of larvae in the root, body, and apex of the tongue from 3 walruses failed to identify a predilection site within the tongue, but the apex was considered an optimal tissue because of the high larval density within the tongue and the ease of collection. All 31 spiked samples weighing 50 g each and containing between 0.1 and 0.4 larvae per gram (lpg) were correctly identified as infected, indicating that the sensitivity of this procedure is adequate for diagnostic use. A sample size of 10 g consistently detected larvae in 2 walrus tongues containing > or = 0.3 lpg (n = 40), and until additional data are available, sample sizes from individual walrus tongues should be a minimum of 10 g. This study provides the preliminary data that were used for the development of a food safety analytical protocol for the detection of Trichinella in walrus meat in arctic communities.     

Effect of dietary Rhodobacter capsulatus on cholesterol, triglycerides concentration, and meat quality of finishing pigs

The study was designed to investigate the effect of Rhodobacter capsulatus on serum and meat cholesterol, fatty acid composition in meat, as well as meat quality of finishing pigs. A total of 16 120-day-old Landrace female pigs of about 60 kg initial body weight were randomly assigned into two groups. The pigs were fed a supplemented diet with 0.04% dietary R. capsulatus or a control diet for 60 days. Total cholesterol and low density lipoprotein-cholesterol concentration in serum was significantly lowered ( P  < 0.05) in the pigs fed the R. capsulatus supplemented diet compared to the control diet. Carcass weight, carcass length, shoulder fat, back fat and loin fat thickness, longissimus muscle (LM) area, and color score did not differ significantly between the pigs fed the R. capsulatus supplemented diet and control diet. Among the nutrient composition of LM meat, neutral fat and triglyceride concentration were significantly ( P  < 0.05) reduced in the finishing pigs by dietary supplementation of R. capsulatus . The proportions of n-6 PUFA were higher ( P  < 0.05) in the pigs fed the R. capsulatus supplemented diet than in the pigs fed the control diet. The supplementation of dietary R. capsulatus to finishing pig diet played important roles in reducing serum cholesterol and meat triglycerides, as well as in increasing polyunsaturated fatty acid content in LM meat.     

Cecal inversion and subsequent colocolic intussusception in a red wolf (Canis rufus gregoryi).

A 2-yr-old female red wolf (Canis rufus gregoryi) presented with weight loss and diarrhea. Abnormal clinical pathology included low serum calcium, sodium, chloride, globulin, and albumin levels. Differential diagnosis included infectious enteritis, intestinal parasitism, inflammatory bowel disease, hepatic or renal disease, and malnutrition. The wolf was treated empirically, but did not improve. A second examination revealed persistent poor musculature and stool quality. Abdominal palpation revealed a firm mass; contrast radiography confirmed an intussusception. Exploratory laparotomy revealed a colocolic intussusception involving the cecum. Following reduction of the colocolic intussusception, cecal inversion (cecocolic intussusception) was identified. Because the cecal inversion could not be reduced, typhlectomy was performed through a colotomy incision. Bacterial culture of peritoneal fluid yielded two strains of Escherichia coli. Postoperatively, the wolf was placed on antibiotics and a soft diet. The diet was gradually returned to its normal formulation and the wolf progressively gained weight. Physical examination 7.5 mo following initial presentation revealed normal body weight and condition. To our knowledge, this is the first recorded incidence of cecal inversion with concurrent colocolic intussusception.     

Increased collagen III in culled chicken meat after feeding dietary wood charcoal and vinegar contributes to palatability and tenderness

We comprehensively evaluated meat quality in chickens fed a diet consisting of wood charcoal and vinegar (WCV) using food scientific and histological approaches. In culled hens, lipid and fatty acid in Musculus semimembranosus, cooking loss and sensory tests of whole thigh meat, and meat texture of breast meat were observed. In male broilers, cross section of M. semimembranosus was used for observations on muscle area, perimysium, non‐collagen total protein and total collagen content, and anti‐collagen I and III reactions. In frozen male broilers, conventional morphology of M. semimembranosus as well as chicken anti‐collagen III reaction to selected muscles of thigh meat and breast meat were compared between the control and WCV‐fed birds. Increased lipid and fatty acids, decreased cooking loss, high score in total evaluation for sensory test of thigh meat, and decreased meat texture values were observed for culled hens fed WCV. The higher values of muscle area, total collagen and collagen III were observed for broilers fed WCV. No perimysium collapse for M. semitendinosus or increased collagen III reactions of M. tensor fasciae latae, the flexor muscle group and M. pectoralis superficialis were observed for frozen muscles in the WCV group. These total results suggest that WCV produces palatable and tender meat by increasing collagen III.     

Amino acid supplementation of meat meal in lysine-fortified, corn-based diets for growing-finishing pigs.

Three experiments involving 320 Yorkshire x Hampshire pigs were conducted to assess the effects of L-tryptophan additions to meat meal-supplemented, corn-based diets on rate and efficiency of growth of growing-finishing pigs. The meat meal used in Exp. 1 and 2 was a blend from two sources and that used in Exp. 3 was from a single source. A fortified corn-soybean meal basal diet (13.3% CP during the growing stage; 11.7 or 12.0% CP during the finishing stage), supplemented with .15 to .20% lysine (as L-lysine.HCl), was fed in each experiment. This diet was formulated to be adequate in dietary lysine (.75 to .80% during the growing stage; .65 to .71% during the finishing stage). Meat meal was added at 5 to 10% and was substituted for corn and soybean meal on a lysine basis. Diets containing meat meal were then supplemented with various levels (0 to .05%) of L-tryptophan. Levels of Ca and P were approximately the same across treatments, with levels based on the amounts provided by the highest level of meat meal in the diets. The pigs initially averaged 24, 29, and 45 kg of BW in the three experiments, and they were on test until they reached market weight (93 to 101 kg of BW). Pigs were switched from the growing to the finishing diet at 57 and 61 kg in Exp. 1 and 2, respectively. Feed intake, growth rate, and efficiency of feed utilization were reduced when meat meal was included in the diet, particularly at the higher dietary inclusion (10%).(ABSTRACT TRUNCATED AT 250 WORDS)     

Collagen fiber arrangement in canine hepatic venules

Cell-maceration/scanning electron microscopy, serial sections and scanning electron microscopy of vascular resin casts were employed to demonstrate the arrangement of collagen fibers in the terminal hepatic venules, involving the central, intercalated and collecting veins in dog liver. In cell-maceration specimens, each collagen fiber was observed to run in various directions, forming a sheath with a compact meshwork of collagen fibers. The collagenous meshwork in the hepatic venules was looser than those of the terminal portal venules and hepatic arterioles. Some collagen fibers formed bundles with an elongated spiral arrangement encircling the wall of the terminal hepatic venules. In resin casts, these venules were observed as a twisted configuration caused by spiral collagen bundles. A helical modification of such connective tissue bundles might provide a mechanically stable vascular structure and permit reversible changes in linear and circumferential vascular dimensions at the terminal tributaries of veins. Round or oval pores with diameters of approximately 9 microns were also observed in the sheath of collagen fibers. These pores, together with the relatively loose collagenous meshwork in the hepatic venules, might play a role in lymphocyte migration from these venules into the surrounding tissue and provide high permeability to the venule walls. No such helical configuration and pores were observed in either the portal venules or the hepatic arterioles.     

Morphological variations in keratinising epithelia in the beagle

Six keratinising epithelia in the beagle have been studied using conventional histology and fluorescence methods to identify the nature of the keratin present. Three patterns of differentiation were identified, those present in areas of hairy skin, the foot pad and the tongue and nasal tip. In the first group, the epidermis is generally thin and exhibits a low mitotic rate but the keratin formed is mature. In the foot pad and tongue, which are examples of pressure keratinisation, the epidermis is appreciably thicker because of the presence of a phospholipid-rich cornified layer. A third form of keratinisation is seen in the nasal tip and in regions of the tongue, characterised by parakeratotic changes, high phospholipid accumulation and other features reported previously in keratinising epithelia subject to prolonged hydration.     

Histopathological observation of stress myopathy in M. longissimus in the pig and relationships with meat quality, fattening and slaughter traits

The characteristic myopathic features revealed by histological observations included strong proliferation of connective and fatty tissue, perivascular infiltrations and necrosis of muscle fibers with phagocytosis to the lesser extent. In the myopathic muscle, as well as in giant fibers, histochemical techniques showed a reduction in succinate dehydrogenase and lactate dehydrogenase activity in type beta R (slow-twitch, oxidative) and alpha R (fast-twitch, oxidative and glycolytic). Magnesium-activated adenosine triphosphatase reaction ranged from diffuse to negative in beta R, alpha R and alpha W (fast-twitch, glycolytic) fiber types. Diffuse reaction for acid phosphatase and total loss of glycogen content were observed. The micrographs of the myopathic muscle indicated enlarged mitochondria with atrophy or complete destruction of cristae. Many myofibrils were hypercontracted. Giant fibers possessed mitochondria enlarged to an even greater extent and many of the myofibrils had loss of continuity, were narrow, depleted and were also hypercontracted. Significant differences between myopathic and normal groups were found in number of beta R fibers (lower in the myopathic group), number of alpha R fibers and percent of alpha R and alpha W fibers (higher in the myopathic group). Differences (P less than .01) existed between meat pH1 value in the myopathic group (mean value of 5.95) and the normal group (mean value of 6.29). Meat from the myopathic group of pigs also had a lower (P less than .01) pH24 value and reduced water-holding capacity (P less than .01) relative to the meat of the normal pigs. The lack of difference of fattening and slaughter traits between the groups suggested that the White Zlotnicka pigs is of particular value because it is possible to improve the production traits without increasing the incidence of these syndromes within the breed. Negative correlations (P less than .05) between number of giant fibers and percent of alpha W fibers, and between percent of giant fibers and percent of alpha W fibers indicate that alpha W fibers can undergo degeneration and be transformed into giant fibers. Therefore, it it suggested that giant fibers should be treated as muscular, pathological results of past stresses and not as an additional type of normal muscle cells.     

Development of muscle spindles in the human tongue

The presence, location and morphology of muscle spindles in the tongue of human fetuses and newborns was examined in frontal and sagittal serial sections of the organ or of the whole lower half of the mouth. While in the fetal material of 105, 155 and 170 mrn. C. R. L. there are only very few and small spindles in some extrinsic muscles of the tongue and in the Mm. mylohyoideus and geniohyoideus, the specimens of 260, 310 and 390mm. C. R. L. showed them in the intrinsic muscles as well as in the extrinsic ones, excludicg only the region of the tip of the tongue. In the latter group, the size of the whole spindles is bigger than in the small fetuses, and their number increases towards the root and the midline area of the tongue. In the newborns, there is the same situation in general, with an especially high number of spindles in the Mm. transversus linguae and genioglossus. The size of the intrafusal muscle fibers was of 6.33 ± 0.72µm. in the newborns, and of 4.93 ± 1.16 pm. in the fetal material; the sheat (capsule) is thinner and the periaxi.11 space is smaller in the minor specimens. As it was possible to find spindles in the muscles of the floor of the mouth in a fetus of the 4th lunar month, there seems to be evidence of the earlier appearance of sum proprioceptors in this region than in other parts of the body, an observation which might implicate some functional significance.     

Production of dark firm dry meat in slaughtered pigs with so-called liver degeneration characterized by yellowish discoloration and high lipid contents

The livers which are discolored yellowish and have a large amount of lipids (liver degeneration) are frequently observed in slaughtered pigs. Dark firm dry (DFD) meat and liver degeneration have a common etiological agent of exhaustion in pigs before slaughter. The correlation between them was examined. In 65 cases of 77 slaughtered pigs with the degenerative liver, which contained more than 6.6% total lipids of liver wet weight, the carcasses showed early rigor mortis and the higher final pH above 6.0. R values of the muscles, which indicated the decrease of ATP, were higher. The meat had a DFD appearance and the muscle fibers had no tendency to shrink. These data showed that the pigs with liver degeneration produced DFD meat at a high rate. In 4 cases of 5 pigs exhausted experimentally by 53 hr fasting and hard exercise before slaughter, both liver degeneration and DFD meat were produced simultaneously. The livers of them were discolored and contained about 8.0% or more total lipids. The carcasses of them showed early rigor mortis and the higher final pH above 6.0. From these data, it was suggested that the exhaustion in pigs before slaughter caused both liver degeneration and DFD meat.     

Effect of dietary oat administration on lipid stability in broiler meat

1. The susceptibility to oxidation of meat from broilers receiving 200 g/kg oats in the diet was compared to the stability of meat from broilers receiving a control diet (10 mg/kg of alpha-tocopheryl acetate) and a diet enriched in alpha-tocopheryl acetate (200 mg/kg). 2. After 9 d of refrigerated storage thiobarbituric acid-reactive substances (TBARS) values in raw dark meat (thigh) were 0.51 and 0.19, respectively, for broilers fed on the control and the alpha-tocopheryl acetateenriched diets. Meat from broilers fed on the diet containing oats had a lower TBARS value than the control group (P 0.05), but higher than the group receiving the supplemented diet. The same trend was observed in white meat (breast). Similar effects were observed after the frozen storage of meats, although the antioxidant effect of oats was more evident (P 0.05) than in the raw meat. 3. Cholesterol oxidation products (COPS) in broiler meat were also influenced by the dietary regimen. COPS concentration in white and dark meat, respectively, from broilers fed on the oat diet were 43% and 32% lower than those in the control samples. 4. Supplemental alpha-tocopheryl acetate reduced COPS concentration by approximately 60%. The availability of natural antioxidants and their possible synergistic effects suggest an interesting way of improving meat stability.     

饲粮中添加过瘤胃蛋氨酸、过瘤胃赖氨酸对荷斯坦奶公牛肉用生产性能和肉品质的影响

本试验旨在研究在饲粮中添加过瘤胃蛋氨酸(RPMet)、过瘤胃赖氨酸(RPLys)对荷斯坦奶公牛肉用生产性能和肉品质的影响。采用完全随机试验设计,选择25头12月龄左右、体重相近的健康荷斯坦奶公牛,随机分为5组,每组5个重复,每个重复1头。对照组饲喂基础饲粮(牧场实用饲粮);其余4个试验组分别在基础饲粮中添加RPMet 15 g/d(RPM组)、RPLys30 g/d(RPL组)、RPLys 30 g/d+RPM et 15 g/d(RPL+M组)和RPLys 30 g/d+RPM et 15 g/d(同时基础饲粮粗蛋白质水平降低1.71%)[RPL+M(L)组]。预试期10 d,正试期150 d。结果表明:1)RPL+M组和RPL+M(L)组试验牛末重、平均日增重均显著高于对照组(P0.05),料重比显著低于对照组(P0.05),但这2组间差异不显著(P0.05);RPL+M(L)组养殖效益最高,为7.67元/(d·头),且高出RPL+M组0.32元/(d·头)。2)与对照组相比,饲粮中添加RPM et、RPLys对荷斯坦奶公牛净肉率无显著影响(P0.05);RPM组、RPL组、RPL+M组和RPL+M(L)组宰前活重显著增加(P0.05),且以RPL+M组最高,但RPL+M组与RPL+M(L)组无显著差异(P0.05);RPL组屠宰率显著升高(P0.05);各试验组胴体产肉率和肉骨比均显著增加(P0.05),但试验组间差异不显著(P0.05)。3)饲粮中添加RPMet、RPLys对眼肌面积、剪切力、熟肉率、大理石花纹等级、p H和肉色等级均无显著影响(P0.05)。4)饲粮中添加RPMet、RPLys对肌肉脂肪酸组成亦无显著影响(P0.05)。综上所述,在饲粮中添加RPM et、RPLys可保持奶公牛同等的肉品质和肌肉脂肪酸含量,并在一定程度上提高奶公牛肉用生产性能;且添加RPMet和RPLys可替代部分蛋白质饲料,增加养殖效益。