Utilization of grass silage by cattle: effect of supplementation with different sources and amounts of protein.

Forty-eight crossbred beef steer calves, initial live weight of 260 kg, were used to examine production responses when grass silage was supplemented with fish meal (FM) or soybean meal (SBM) during a 210-d feeding period. The silage was available on an ad libitum basis either alone or supplemented with 100, 225, 350, or 500 g of FM or 600 g of SBM/d. Increasing levels of FM resulted in a linear increase in live weight gain (P < .001) and gain:feed ratio (P < .001). The FM supplementation had no effect (P = .79) on silage DM intake. The FM supplement increased plasma albumin concentration (P < .05) but did not affect plasma glucose (P > .20) The steers were shipped to market when they had 8 mm of fat over the longissimus muscle as determined by ultrasound. Sensory evaluation of roasts from steers fed 0, 225, 350, or 500 g/d of FM indicated a positive linear (P < .01) increase in flavor and decrease in juiciness as FM level increased. There were no differences (P > .15) in live weight gain, intake, or gain:feed ratio between isonitrogenous supplements of FM and SBM. However, the additional gain resulting from SBM and FM indicated that, on a crude protein basis, SBM was approximately 80% as effective as FM in increasing live weight gain in steers fed grass silage.

Feed efficiency, carcass characteristics, and sensory quality of lambs, with or without prolific ancestry, fed diets with different protein supplements.

Data were collected on 130 intact male lambs fed diets based on roughages supplemented with fish meal, soybean meal, or corn gluten-blood meal and slaughtered at 43 kg live weight. A nonsupplemented group served as a control. The lambs represented Romanov (R), Finnsheep (F), a new breed developed in Canada (DLS), Coopworth (C), and Suffolk (S), three first crosses of DLS with R, F, and Booroola Merino (B), and their backcrosses to DLS. Supplemented lambs consumed 16 to 22% less (P less than .05) silage than control lambs. Average daily gains of lambs fed fish meal (226 g) and corn gluten-blood meal (217 g) were higher and feed conversion ratio (4.99 and 5.11) lower than that of lambs fed soybean meal (189 g and 5.48) or control (186 g and 5.76) diets (P less than .05). The cost of feed per kilogram of gain or per kilogram of lean produced was similar in the four treatments but was between C $.23 and .65 cheaper in the protein-supplemented groups when the number of days to reach slaughter weight was considered. The effect of diet on carcass traits and meat quality were minimal. Meat of lambs fed the three protein supplements was less juicy than that of control lambs. With a few exceptions, most of the significant differences among genetic groups in growth, carcass, and sensory traits were mainly between prolific (R and F) and meat-type breeds (C, S, and DLS). Gain in weight was highest in S lambs (199 g/d), but F and R first crosses were the youngest at slaughter (196 and 198 d). The F lambs had higher dressing and kidney fat percentages than meat-type breeds. The DLS lambs had the largest longissimus muscle area (14.0 cm2), whereas C had the smallest (10.7 cm2). The B crosses had larger longissimus muscle area than R and F crosses. The R lambs had more lean and less fat in the 12th rib, whereas C lambs had the lowest lean and a high bone percentage. The toughest and the most tender roasts were those of R and B crossbred lambs, respectively. Roasts from F lambs had the most intense lamb flavor.

Microstructural manifestations of two unusual phenomena detected in experimental roast pork: A scanning and transmission electron microscopy study.

Loin roasts L. dorsi from both barrows and gilts from a breeding and feeding experiment were cooked, cut, presented to sensory evaluation panelists and the excess meat stored at 4°C in tied plastic bags. An interesting phenomenon observed was that a deposit remained on the cutter blade after slicing the experimental roasts, but no deposit remained in the blade after cutting control roasts. Similarly, slices of experimental roast adhered together after refrigeration, but slices of control roast stored under identical conditions did not stick together. Electron microscopic examination showed that the experimental samples were made up of three zones consisting of fat, collagen and muscle tissue. The thickness of the middle (collagen) zone varied with the sex of the animals and possibly with their genetic background. Where the experimental roast slices adhered, they always did so only at the middle collagen layer. In contrast, control samples were made up of only two layers: fat and muscle, with the collagen layer between them being absent or much reduced in thickness.

Oat gum lowers glucose and insulin after an oral glucose load.

Foods containing soluble dietary fibers delay glucose absorption and lower postprandial plasma glucose. This effect of oat bran has been attributed to oat gum (80% beta-glucan). However, purified oat gum has previously not been available for human studies. In this study the glucose and insulin responses to consuming 14.5 g of specifically prepared oat gum with 50 g glucose were compared with the response to guar gum with glucose and to glucose alone in nine healthy, fasting subjects. Plasma glucose and insulin increases after the glucose drink were greater than after both gum meals between 20 and 60 min (P less than 0.01). The responses to the two gum meals were nearly identical. These results establish that the more palatable oat gum lowers postprandial plasma glucose and insulin concentrations in humans and may be comparable with or of greater benefit than guar gum.

A sensory perspective of effect of feeds on flavor in meats: poultry meats.

Reduction of feed costs is a major concern of poultry producers. However, replacement of components of a corn-soybean diet with a lower-cost alternative requires the assessment not only of poultry performance and carcass characteristics but also of resulting meat quality. A brief overview of research studies, conducted over the past 10 yr, investigating the effects of alternative poultry feedstuffs on poultry meat flavor is presented. The primary focus is on the sensory analysis technique employed in these studies to evaluate flavor. The studies discussed include examinations of poultry diets that contain various levels of rapeseed meal, fishmeal and other feed additives. Diversity of the sensory techniques used illustrates the difficulty of comparing sensory results among studies. This difficulty is emphasized further with an example of how two different sensory sample preparation techniques affected the conclusion drawn from replicate studies of poultry diets supplemented with fishmeal (0, 4, 8 and 12%). One of the replicates was cooked and sampled for sensory analysis; the other was placed in 4 degrees C storage overnight. For the samples tested immediately following cooking, no difference between the treatments was detected. However, when the samples were tested following overnight storage (4 degrees C), chicken flavor decreased (P less than .001) and fish-off flavor increased (P less than .001) as percentage of fish meal in the diet increased.

Effect of low voltage electrical stimulation on the distribution of cathepsin D and the palatability of the Longissimus dorsi from Holstein veal calves fed a corn or barley diet.

Forty male Holstein veal calves (45 kg) were weaned on milk replacer given once or twice daily and fed either a corn or a barley diet until slaughter at 215 kg liveweight. Carcasses from half of the animals on each diet were assigned to low-voltage electrical stimulation (LVES), the other half served as controls. LVES accelerated the pH drop of the meat (P<0·01) and resulted in a more rapid liberation of cathepsin D (P < 0·01) in the soluble fraction of the longissimus dorsi homogenate. Despite the faster liberation of cathepsin D, meat samples from the LVES group were tougher than those of controls (P < 0·01). Meat colour measured by reflectance was not affected by the post-mortem treatments but ageing for six days significantly decreased the reflectance measurements (P < 0·01). The meat flavor was more pronounced for controls and for barley fed animals (P < 0·01). SDS-polyacrylamide gel electrophoresis of the myofibrillar proteins demonstrated that meat ageing favored the degradation of troponin-T (TN-T) and the appearance of a new banding pattern in the 25-35 kdalton region. Compared with controls ES had a tendency to decrease the rate of degradation of TN-T although no difference in the banding patterns could be observed after 6 days of ageing.

Toxin Production by Clostridium botulinum and Organoleptic Changes in Vacuum-Packaged Raw Beef.

Vacuum-packaged beef, inoculated with Clostridium botulinum spores of types A and B and incubated at 25°C, was monitored for the production of toxin and for changes in appearance and odor. Toxin was detected first after 6 d of incubation and was always accompanied by significant organoleptic changes when compared to meat stored at 4°C. Uninoculated meat samples stored at 25°C remained non-toxic, whereas their sensory scores, in particular with respect to appearance, were similar to those of the inoculated samples.