A sensitive method for the determination of amitriptyline and nortriptyline in human plasma

The kinetics of the male gametogenesis during the pregonadal period, prespermatogenesis, and "early" spermatogenesis has been described in detail. Concerning spermatogenesis in the adult individual reference is made to the articles of Courot, Hochereau-de Reviers and Ortavant (1970) and of Clermont (1972). The comparison of female and male gametogenesis (Fig. 1) shows that the "gonia stage" (asterisks) of the female germ cells is limited to one proliferation wave only, whereas the "gonia stage" of the male germ cells consists of a first proliferation wave, comparable to that of oogonia, a preparative phase to initiate spermatogenesis, and a second proliferation wave with renewal and differentiation of the spermatogonia. Germ cells in the "gonia stage" are highly sensitive towards ionising radiation and cytostatic drugs.     

Effects of intrajugular glucose infusion on feed intake,milk yield,and metabolic responses of early postpartum cows fed diets varying in protein and starch concentration

Effects of glucose infusion on feed intake, milk production, and metabolic responses of early postpartum cows fed diets varying in starch and protein concentration were evaluated by utilizing a randomized complete block design with a 2 × 2 factorial arrangement of treatments. Twenty-four multiparous Holstein cows were blocked by body condition score and 305-d mature-equivalent milk yield and randomly assigned at calving to 1 of 4 treatments. Treatments were continuous intrajugular infusion of glucose (GI) or isotonic saline (SI), and diets containing high starch, low crude protein (HSLP) or high crude protein, low starch (HPLS) concentrations. Treatments were initiated at the first scheduled feeding following parturition and lasted 12 d. The GI reduced cumulative dry matter intake and tended to reduce daily dry matter intake and meal size for HPLS but not HSLP compared with SI. The GI increased cumulative milk yield by 39 kg/12 d compared with SI by increasing it for HSLP but not HPLS. The HPLS treatment tended to increase loss of body condition from 0.65 to 0.82 body condition score units/12 d compared with HSLP. Consistent with this, HPLS increased plasma concentrations of nonesterified fatty acids, β-hydroxybutyrate, liver triglyceride, milk fat concentration and yield, 3.5% fat-corrected milk, and milk urea nitrogen compared with HSLP. Overall, the GI-HPLS treatment reduced feed intake by reducing meal size. The GI-HPLS may have reduced meal size by the independent or additive effects of (1) decreasing hepatic gluconeogenesis and promoting oxidation of acetyl coenzyme A (CoA), (2) elevated plasma nonesterified fatty acids from HPLS increasing the pool of acetyl CoA available to be oxidized, and (3) the HPLS diet increasing urea synthesis, which also provides the tricarboxylic acid cycle intermediate fumarate to promote oxidation of acetyl CoA.     

Non-destructive assessment of instrumental and sensory tenderness of lamb meat using NIR hyperspectral imaging

The purpose of this study was to develop and test a hyperspectral imaging system (900–1700 nm) to predict instrumental and sensory tenderness of lamb meat. Warner–Bratzler shear force (WBSF) values and sensory scores by trained panellists were collected as the indicator of instrumental and sensory tenderness, respectively. Partial least squares regression models were developed for predicting instrumental and sensory tenderness with reasonable accuracy (R_cv = 0.84 for WBSF and 0.69 for sensory tenderness). Overall, the results confirmed that the spectral data could become an interesting screening tool to quickly categorise lamb steaks in good (i.e. tender) and bad (i.e. tough) based on WBSF values and sensory scores with overall accuracy of about 94.51% and 91%, respectively. Successive projections algorithm (SPA) was used to select the most important wavelengths for WBSF prediction. Additionally, textural features from Gray Level Co-occurrence Matrix (GLCM) were extracted to determine the correlation between textural features and WBSF values.     

Luteal maintenance of pregnancy in the African elephant (Loxodonta africana)

The ovaries of eight African elephant foetuses and their mothers between 2 and 22 months of gestation, and those of two cycling and two lactating elephants, were examined grossly, histologically and immunocytochemically, with emphasis on the development and regression of accessory corpora lutea (CL) of pregnancy and the steroidogenic capacities of the accessory CL and the foetal ovaries. The results supported recent findings that the accessory CL form as a result of luteinisation, with and without ovulation, of medium-sized follicles during the 3-week inter-luteal period of the oestrous cycle. They enlarge significantly and become steroidogenically active around 5 weeks of gestation, probably in response to the placental lactogen which is secreted by the implanting trophoblast of the conceptus. The large luteal cells stained strongly for 3β hydroxysteroid dehydrogenase (3βHSD) activity throughout the 22-month gestation period although they showed vacuolation and other degenerative changes in the final months of gestation coincident with hypertrophy and hyperplasia of 3βHSD-positive interstitial cells in the foetal gonads. It is proposed that the progestagens secreted by the enlarged gonads of the elephant foetus may function both to assist the maternal ovaries in supporting the pregnancy state and to induce torpor and intrauterine immobility of the rapidly growing foetus.     

Nutrient demand interacts with forage family to affect digestion responses in dairy cows

Effects of forage family on dry matter intake (DMI), milk production, ruminal pool sizes, digestion and passage kinetics, and chewing activity and the relationship of these effects with preliminary DMI (pDMI), an index of nutrient demand, were evaluated using 13 ruminally and duodenally cannulated Holstein cows in a crossover design with a 14-d preliminary period and two 18-d treatment periods. During the preliminary period, pDMI of individual cows ranged from 19.6 to 29.5 kg/d (mean=25.9 kg/d) and 3.5% fat-corrected milk yield ranged from 24.3 to 60.3 kg/d (mean=42.1 kg/d). Experimental treatments were diets containing either a) alfalfa silage (AL) or b) orchardgrass silage (OG) as the sole forage. Alfalfa and orchardgrass contained 42.3 and 58.2% neutral detergent fiber (NDF) and 22.5 and 11.4% crude protein, respectively. Forage:concentrate ratios were 60:40 and 43:57 for AL and OG, respectively; both diets contained approximately 25% forage NDF and 30% total NDF. Preliminary DMI was determined during the last 4 d of the preliminary period when cows were fed a common diet and used as a covariate. Main effects of forage family and their interaction with pDMI were tested by ANOVA. Forage family and its interaction with pDMI did not affect feed intake, milk yield, or milk composition. The AL diet increased indigestible NDF (iNDF) intake and decreased potentially digestible NDF (pdNDF) intake compared with OG. The AL diet increased ruminal pH, digestion rates of pdNDF and starch, and passage rates of pdNDF and iNDF compared with OG, which affected ruminal digestibility. Passage rate of iNDF was related to pDMI; AL increased iNDF passage rate and OG decreased it as pDMI increased. The AL diet decreased ruminal pool sizes of pdNDF, starch, organic matter, dry matter, and rumen digesta wet weight and volume compared with OG. The AL diet decreased ruminating time per unit of forage NDF consumed compared with OG, indicating that alfalfa provided less physically effective fiber than orchardgrass. The AL diet, but not OG, increased ammonia N, nonammonia nonmicrobial N, and nonammonia N fluxes as pDMI increased. Efficiency of microbial protein synthesis was positively related to pdNDF passage rate for OG, but not AL. The faster rates of digestion and passage for AL compared with OG decreased rumen pool size but did not increase feed intake for cows consuming AL. Digestion responses to forage family were affected by nutrient demand of cows.     

Effects of corn grain endosperm type and conservation method on feed intake,feeding behavior,and productive performance of lactating dairy cows

Our objective was to evaluate the effects of corn grain varying in endosperm type and conserved as high-moisture or dry ground corn on dry matter intake (DMI), feeding behavior, ruminal fermentation, and yields of milk and milk components of cows in early to mid-lactation. Seven ruminally and duodenally cannulated Holstein cows (73 ± 39 d in milk; mean ± SD) were used in a duplicated 4 × 4 Latin square design with 21-d periods. A 2 × 2 factorial arrangement of treatments was used with main effects of corn grain endosperm type (floury or vitreous) conserved as high-moisture corn (HMC) or dry ground corn (DGC). Rations were formulated to contain 27.0% starch, 26.6% neutral detergent fiber (NDF), 19.1% forage NDF, and 16.5% crude protein. Corn grain treatments supplied 86.6% of dietary starch and contained alfalfa silage as the sole forage. Dry matter intake was increased 1.3 kg/d by DGC compared with HMC. The increase in DMI by DGC was related to a shorter intermeal interval (104.4 vs. 118.2 min/d), and meal size was not affected by treatment. Dry ground corn decreased rumination bout length and number of chews per bout compared with HMC. No differences were detected between endosperm treatments for DMI, yields of milk, 3.5% fat-corrected milk (FCM), milk fat, protein, lactose, or solids-not-fat (SNF). Mean yield of 3.5% FCM across treatments was 47.5 kg/d. However, a tendency for an interaction was observed for feed efficiency; floury endosperm increased efficiency 0.05 kg 3.5% FCM per kg of DMI for DGC but decreased it by 0.14 kg 3.5% FCM per kg of DMI for HMC relative to vitreous endosperm. Vitreous compared with floury corn tended to increase true protein concentration in milk when conserved as DGC (2.68% vs. 2.62%) but not as HMC. Concentration of SNF was increased by DGC compared with HMC (8.45 vs. 8.37%) due, in part, to the effect of treatment on milk protein concentration. Body weight was not affected by treatment, but vitreous endosperm tended to increase loss of body condition compared with floury endosperm. Corn endosperm type and conservation method had little effect on productive performance of high-producing cows.     

The Effect of Post-Cooking Holding Times on Sensory Assessment of Low- and High-Fat Beefburgers

ABSTRACT: The effect of post-cooking holding-time on sensory assessment of low (89 g/kg) and high (218 g/kg) fat beefburgers was assessed. Burgers were served to panelists approximately 3 or 18 min after cooking. Fat content influenced fattiness, moistness/juiciness and overall appearance (P < 0.05), overall acceptability and overall texture (P< 0.01) and tenderness and crumbliness (p<0.001). Burgers with the higher fat content had higher scores. Holding-time influenced sensory overall appearance only with lower scores at extended holding times (P < 0.01). Treatment differences were small, mostly less than one sensory scale unit. Higher lightness and yellowness values were found for burgers with higher fat contents.     

Evaluation of high humidity and wet marinade methods for pasteurization of jerky

ABSTRACT:  The USDA FSIS meat and poultry jerky compliance guidelines recommend a high humidity or liquid immersion pasteurization step before drying. The objective of this study was to evaluate the effects of high humidity (>90%) or wet marinade pasteurization on jerky characteristics (water activity, moisture/protein ratio, total aerobic plate count [TAC]) and sensory properties. Jerky pasteurized by nonmarinade method A (76.6 °C dry bulb, 54.4 °C oven wet bulb temperature for 1 h) had highest sensory scores for spice intensity and interior cured color (redness), and generally lower TACs than jerky from marinade pasteurization methods. Jerky pasteurized by method B (54 °C for 121 min in marinade) had higher TACs than other methods. Approximately 2-log reduction in TAC was observed using marinade pasteurization in the smokehouse to internal temperature of 60° for 12 min (method C), or in hot marinade to internal temperature of 70 °C before drying (method D), but jerky was less spicy and somewhat darker than jerky from method A. Extruded jerky (1.5-cm thickness) was similar to intact jerky for spice flavor intensity and interior redness, but required longer drying time to reach the target Aw of 0.85. Marinade pasteurization by methods C or D was feasible, and may be a preferred alternative for some processors, since monitoring of oven humidity during pasteurization is not necessary.     

Depression in feed intake by a highly fermentable diet is related to plasma insulin concentration and insulin response to glucose infusion

The effects of dietary starch fermentability on feed intake and nutrient digestibility were evaluated in a crossover study, which was also designed to find factors that predict individual variation in feed intake response to starch fermentability. Thirty-two multiparous Holstein cows (121 ± 48 d in milk, 44 ± 7 kg/d of milk yield; mean ± SD) were randomly assigned to treatment sequence and were fed a diet intermediate to the treatments during a preliminary 28-d period. Treatments were dry ground corn grain and high-moisture corn harvested from the same field. Treatment periods were 14 d, with the final 4 d used for data and sample collection. Diets included corn silage and alfalfa haylage at a 2:1 ratio and were 26% neutral detergent fiber, 17% crude protein, 32% starch, and 3.5% fatty acids. High-moisture corn decreased dry matter intake (DMI) by 8%, but did not significantly alter digestible DMI. Individual DMI responses were highly variable, and variables from preliminary plasma analyses, propionate challenge tests, glucose tolerance tests, and hepatic mRNA analysis were assessed as potential predictors of DMI response to increased dietary starch fermentability. Of the covariates tested, only preliminary plasma insulin concentration and insulin response to glucose infusion were significant predictors of DMI response. High preliminary plasma insulin concentration was correlated with greater depression in DMI with increased fermentability; conversely, greater insulin secretion in response to glucose infusion was associated with minimal depression in DMI. These insulin variables were not significantly correlated. Consistent with past results, increased dietary starch fermentability decreased DMI. Significant correlations between insulin variables and individual DMI responses may warrant further investigation.