High Feeding Level Research Articles

Enhancement of oleic acid and vitamin E concentrations of bovine milk using dietary supplements of whole rapeseed and vitamin E

With the aim of reducing the degree of saturation and increasing the C18:1 cis fatty acid content of milk fat, the effects of feeding high levels of whole cracked rapeseed to dairy cows was in- vestigated together with the effect of increasing dietary intake of vitamin E on the vitamin E content of milk. Usin ga3×3f actorial design, 90 Holstein dairy cows were fed one of three levels of whole cracked rapeseed (0 (ZR), 134 (MR) and 270 g·kg -1 diet dry matter (DM) (HR)) in combination with one of three intakes of supplementary vitamin E (0 (ZE), 2 (ME) and 4 g·cow -1 ·d -1 (HE)). Supple- menting with up to almost 2 kg·d -1 of rapeseed oil (diet HR) significantly (P < 0.001) increased C18:1cis in milk fat, from 181 (ZR) to over 400 g·kg -1 (HR) of total milk fatty acids. Concentrations of C18:0, C18:2 and C18:3 fatty acids were also increased (P < 0.001) but by a much lesser degree, and the saturated fatty acids C4:0 to C16:0 decreased substantially. Vitamin E supplementation in- creased (P < 0.01) milk vitamin E concentrations from 1.29 (ZE) to 1.68 mg·kg -1 whole milk (HE). Thus substantial changes in milk fat composition with potentially beneficial effects on human health were achieved and without any adverse effects on milk taste. However, these improvements must be offset against the substantial reductions (P < 0.001) observed in voluntary feed DM consumption (ZR, 20.6; HR, 15.2 kg DM·d -1 ), milk yield (ZR, 22.9; HR, 13.2 kg·d -1 ) and milk fat concentration (ZR, 42.1; HR, 33.4 g·kg -1 ) which would not be commercially sustainable unless a considerable pre- mium was paid for this modified milk. It seems likely that the optimum dose of dietary rapeseed is lower than used in this study.

Changes in feeding level during early pregnancy affect fertility in gilts

Modified feeding combining the benefits of restricted feeding after ovulation and abundant feeding during implantation in autumn was tested. Three groups of eight gilts were housed with individual feeding stalls and fed 40 MJ per day of a commercial ration. Following insemination gilts were fed 27 MJ per day (LLL) or 54 MJ per day (HHH) for 34 days or 27 MJ per day for 10 days, 54 MJ per day for 7 days followed by 27 MJ per day until day 34 (LHL). Blood for progesterone analysis was collected daily during the week of ovulation and then twice a week until the end of the study. For LH assay, blood was collected from five gilts from each group at 15 min interval for 10 h on the day 15 of pregnancy. Gilts were weighed three times at intervals of 4 weeks. The effect of dietary treatment was significant ( P<0.05) on body weight gain from days 0 to 30 of pregnancy, 1201, 287 and 438 g per day for groups HHH, LLL and LHL respectively. The pregnancy rate at day 34 was significantly higher ( P<0.005) in HHH-group (100%) compared with LLL (25%) and LHL (38%) although HHH group had significantly lower ( P<0.05) progesterone concentration on days 9 and 12. The basal LH level was significantly higher ( P<0.01) in HHH group compared to LHL group (mean±S.D.) (0.98±0.22 and 0.60±0.08, respectively). Gilts in HHH group had a significantly higher mean LH concentration (1.18±0.24) than those in group LHL (0.7±0.07) ( P<0.05), but not in group LLL (0.93±0.15) ( P=0.09). There was a tendency ( P=0.058) for amplitude to be higher for gilts in HHH group. The LHL feeding strategy did not provide the benefits anticipated. Instead, it was the HHH feeding strategy that provided a disfinct advantage in pregnancy rate. The mechanism mediating supportive effect of high feeding level on the maintenance of early pregnancy is yet to be determined.

A subchronic 90-day oral rat toxicity study and in vitro genotoxicity studies with a conjugated linoleic acid product

Conjugated linoleic acid (CLA) is the term given to a group of positional and geometric isomers of the essential fatty acid linoleic acid. CLA is found naturally in foods such as dairy and meat products. CLA is reported to have a number of beneficial effects including anticarcinogenic activity. However, safety data are limited. Clarinol™ G80 is a commercial preparation containing equal amounts of the 9 cis,11 trans and 10 trans,12 cis CLA isomers in the form of glycerides. In order to support the safety-in-use of Clarinol™ G80 as an ingredient in food, the preparation was tested in two in vitro mutagenicity assays, an Ames test and an in vitro cytogenetics assay, and a 90-day repeat-dose oral toxicity rat study. Clarinol™ G80 was non-mutagenic in both in vitro assays. In the 90-day study, Clarinol™ G80 produced hepatocellular hypertrophy in female rats at the highest dose level (15% w/w). This effect was an adaptive effect in response to feeding high levels of Clarinol™ G80 in the diet and was reversible upon withdrawal of test material. An increase in plasma insulin levels was also observed female rats fed 15% w/w Clarinol™ G80 but there was no effect on plasma glucose levels. A No Observed Adverse Effect Level of 2433 mg/kg bw/day for male and 2728 mg/kg bw/day female rats was identified in the study.

Effects of growth hormone and feeding level on endocrine measurements, hormone receptors, muscle growth and performance of prepubertal heifers.

Prepubertal Friesian heifer calves (n = 24, initial BW = 195 +/- 5 kg) were assigned to a 2 x 2 factorial block design and used to evaluate the effects of daily GH treatment (0 or 15 mg/d) at either a low or a high feeding level in a 5-wk treatment period on endocrine measurements, hormone receptors, muscle growth, and overall performance. In the pretreatment period, a low feeding level was employed for all calves. During the treatment period, animals at the low feeding level had free access to a roughage-based mixture, whereas animals at the high feeding level had free access to a concentrate mixture and were offered 2 kg/d of the roughage-based mixture. Blood samples were collected weekly starting 3 wk before treatment. Longissimus (LM) and supraspinatus (SS) muscles were obtained at slaughter. Metabolizable energy intake was 81% higher, digestible CP intake was 140% higher, and ADG was 115% higher (all P < 0.001) at the high vs. low feeding level. Feed (DMI, ME, and protein) intake was not affected by GH treatment, but ADG was 18% higher (P < 0.13) in GH-treated than in control heifers at both feeding levels. Although of different magnitudes, the muscle anabolic effects of GH treatment and high vs. low feeding level were additive, and both treatments increased carcass weights (P < 0.02 and P < 0.001, respectively), LM (P < 0.05 and P < 0.001), and SS (P < 0.06 and P < 0.003). The anabolic effect of GH treatment was similar in both muscles, whereas the effect of feeding level was most pronounced in LM. Overall, GH treatment increased plasma GH, IGF-I (both P < 0.001), and IGFBP-3 (P < 0.02); however, GH treatment increased total IGF-I, free IGF-I, and IGFBP-3, and decreased IGFBP-2 mainly at the high feeding level (GH x feeding level interaction; P < 0.02, 0.01, 0.03, and 0.10, respectively). The high feeding level increased insulin, free and total IGF-I, and IGFBP-3 (all P < 0.001), but decreased GH and IGFBP-2 (both P < 0.001). High feeding increased type-1 IGF receptor density (P < 0.02), mainly in LM, in accordance with the largest anabolic response in this muscle, whereas GH treatment had no effect on type-1 IGF receptors. The results suggest that in skeletal muscle, the anabolic effects of exogenous GH are related to endocrine changes in the GH-IGF axis, whereas the effects of feeding level also seem to rely on IGF receptor density in the muscles.

Combined effects of copper and food on the midge Chironomus riparius in whole-sediment bioassays

Effects observed in whole-sediment bioassays must be seen as the joint effect of all sediment characteristics. In whole-sediment bioassays, however, adverse effects on test organisms are usually attributed to the presence of contaminants and effects of food are often ignored. The aim of this study was to analyze the response of the midge Chironomus riparius to sediment spiked with different combinations of food and copper. The responses of C. riparius to these spiked sediments were assessed in 10-day whole-sediment bioassays. Decreases in survival, dry weight, and length of C. riparius were observed with increasing copper concentrations. However, an increase in the amount of food resulted in an increase of larval dry weight and length until copper concentrations reached a critical threshold of 200 mg/kg. In addition, an increase in the amount of food resulted in a decrease of accumulated copper in the larvae. The present study demonstrated that the combination of copper and food in the sediment determines the performance of C. riparius in whole-sediment bioassays. The dependency of C. riparius on high feeding levels, which mask toxic effects, questions its suitability as a test organism for whole-sediment bioassays. Because benthic communities in polluted ecosystems are often exposed to varying levels of both food and toxicants it is concluded that the trophic state of the ecosystem may alter the ecological risk of sediment-bound toxicants to opportunistic benthic invertebrates such as C. riparius.

Effects of dietary protein content and food intake on carcass characteristics and organ weights of growing Iberian pigs

AbstractThe effects of dietary protein content and level of feeding on carcass characteristics and organs weight were evaluated in 72 male castrated Iberian pigs growing from 15 to 50 kg live weight. Animals were offered six diets providing 223, 192, 175, 156, 129 and 101 g crude ideal protein (CP) (N × 6·25) per kg dry matter (DM) and 14·64, 14·14, 14·37, 14·80, 15·36 and 15·53 MJ metabolizable energy (ME) per kg DM, respectively. Each diet was offered at three levels of feeding : 0·60, 0·80 and 0·95 × ad libitum intake. Mean values of protein, fat, ash and water contents in the carcass determined at 50 kg live weight were 130, 378, 28·2 and 458 g/kg, respectively, with a small but significant effect of CP content of the diet on carcass composition (P &lt;0·001 to P &lt;0·01) favouring both protein and fat content on decreasing dietary protein level. Protein deposition (PD) in the eviscerated carcass reached a maximum value when the diet containing 129 g CP per kg DM was offered (54·6 g/day at the highest feeding level). Nitrogen (N) retention in the carcass represented 70·9% of whole-body N retention and the efficiency of this process (carcass N retention : N intake) increased with declining dietary protein content (P &lt;0·001). Carcass energy retention increased significantly with decreasing dietary CP content (P &lt;0·001) and with feeding level (P &lt;0·001). Raising energy intake resulted in a significant increase on total weight of viscera as proportion of empty body weight (P &lt;0·001). Decreasing the CP content in the diet resulted in a lower proportional shoulder weight (P &lt;0·01) meanwhile the proportion of ham decreased significantly (P &lt;0·05) with increase in feeding level. The proportionate weights of dissectable fat in the shoulder and of intermuscular and subcutaneous fat in the ham increased significantly (P &lt;0·05 and P &lt;0·001) in response to decreasing dietary CP content meanwhile only ham intermuscular fat content increased with feeding level (P &lt;0·001). Thus, decreasing dietary protein concentration from well in excess of requirements and increasing energy intake enhance N and fat retention in the carcass but also increases intermuscular fat content in the ham of the Iberian pig with possible implications for meat quality.

Effect of pre- and postmating nutritional manipulation on plasma progesterone, blastocyst development, and the oviductal environment during early pregnancy in gilts.

Two experiments were conducted to determine mechanisms mediating effects of nutritional manipulation before and after mating on embryonic survival in pigs. Experiment 1 studied the mechanisms by which continued high feeding levels after mating result in differences in plasma progesterone during early pregnancy. Gilts fed 2.0 times maintenance energy requirements either remained on this high level or feed was reduced to 1.5 times maintenance immediately after mating. Ovarian, oviductal, and jugular vein progesterone concentrations were determined 72 h after onset of estrus, and samples taken every 4 h were used to determine LH and progesterone during the periestrous period. Treatment did not affect peripheral progesterone concentrations, the timing or rate of rise of progesterone, or progesterone in ovarian, oviductal, or jugular veins at the time of surgery. Time after the LH peak was highly correlated (P = 0.0001) with jugular progesterone concentrations, but not with those in oviductal and ovarian veins, suggesting that responses in the reproductive tract mediated by peripheral progesterone concentrations will be temporally different to effects within tissues supplied by the ovarian and oviductal vasculature. Experiment 2 studied mechanisms mediating nutritional manipulation in the preovulatory period on postovulatory reproductive function, using feed restriction during the first (RH) or second (HR) week of the estrous cycle. Surgeries were performed 12 to 20 h after ovulation, and fertilized oocytes were cultured for 144 h in vitro. Ovulation rate was not affected by previous nutritional regimen. Fertilization rate was higher (P = 0.056) in RH vs HR gilts, but development of cultured oocytes was not affected by treatment. There were no treatment differences in peripheral or oviductal plasma progesterone, estradiol, or insulin-like growth factor-I (IGF-I) at surgery, or in porcine oviductal secretory protein abundance and IGF-I concentrations in oviduct flushings, but treatment affected total protein concentration (P = 0.002). These results indicate that either previous nutritional treatment does not affect the early developmental competence of fertilized oocytes in vitro or differences in developmental competence of oocytes are not expressed up to the early blastocyst stage. However, the lack of an effect of previous nutrition on steroids in the local oviductal circulation may also be related to the lack of effects on oviductal function and embryonic development.

Changes in single unit activity in the lateral hypothalamic areaof goats during feeding1

In order to clarify the location of feeding centers in the ruminant brain, this study used a single-unit activity (SUA) recording electrode to investigate the existence of appetite-regulating neurons in the lateral hypothalamic area (LHA) in goats. Seven male Japanese Saanen goats were used in the experiment. The animals were fed twice daily, once in the morning (1000 to 1200) with 1.5 kg of roughly crushed alfalfa hay cubes, and once in the afternoon (1600 to 1800) with 200 g of commercial ground concentrate feed. The animals were allowed free access to drinking water. In this study, the animals were surgically operated on to position the recording electrode in the LHA. Recordings of SUA were carried out continuously over a 2.25-h period beginning 15 min prior to the commencement of morning feeding. The eating rates of crushed alfalfa hay cubes were highest 10 min after feeding commencement, but decreased sharply by the time 40 min had elapsed. The cumulative feed intake after the completion of the 2-h feeding period was 1164 +/- 38 g. The cumulative water intake upon the conclusion of the 2-h feeding period was 2422 +/- 107 mL. This study recorded 31 units, of which five showed a response to feeding and altered their firing rates. In response to a sharp increase in eating rates, all five units increased their firing rates to a level higher than that of prefeeding (P < 0.05). As the animals reached a level of satiety (eating rates declined to very low levels), firing of units I and II stopped completely, while the firing rates of units III, IV, and V decreased. Examination of a serial histological section confirmed that the five units in which changes in firing rates with feeding were observed were all located in the dorsolateral hypothalamic area close to the fornix. The LHA neurons recorded in this experiment characteristically showed neuronal activity increases at high levels of feeding, but decreases at low levels. The results suggest that there are cells located in the LHA of goats that are active in the physiological regulation of hay (dry forage) intake.

Limiting factors in Escherichia coli fed-batch production of recombinant proteins.

Fed-batch production of recombinant beta-galactosidase in E. coli was studied with respect to the specific growth rate at induction. The cultivations were designed to induce protein production by IPTG at a glucose feed rate corresponding to high mu = 0.5 h(-1)) or low (mu = 0.1 h(-1)) specific growth rate. Protein production rate was approximately 100% higher at the higher specific growth rate, resulting in the accumulation of beta-galactosidase up to 30% of the total cell protein. Transcription analysis showed that beta-galactosidase-specific messenger RNA was immediately formed after induction (<5 min), but the amount was the same in both cases and was thus not the initial limiting factor. The content of ribosomes, as represented by rRNA, rapidly decreased with specific growth rate from a relative level of 100%, at the high specific growth rate, to 20% at the low specific growth rate. At high specific growth rate, ribosomes were additionally degraded upon induction due to the high production level. Translation therefore seemed to be the initial limiting factor of the protein synthesis capacity. The alarmone guanosine tetraphosphate increased at both high and low feed level inductions, indicating an induction-forced starvation of charged tRNA and/or glucose. The altered physiological status was also detected by the formation of acetic acid. However, the higher production rate resulted in high-level accumulation of acetic acid, which was absent at low feed rate production. Acetic acid production is thus coupled to the high product formation rate and is proposed to be due either to a precursor drain of Krebs cycle intermediates and a time lag before induction of the glyoxalate shunt, or to single amino acid overflow, since the model product is relatively poor in glycin and alanin. In conclusion, it is proposed that production at high specific growth rate becomes precursor-limited, while production at low specific growth rate is carbon- and/or energy-limited.

Effects of dietary vitamin E on chickens infected with eimeria maxima: observations over time of primary infection.

Two trrials were conducted to define temporal changes in plasma D-alpha-tocopherol (AT) caused by infection with Eimeria maxima in chickens that consumed either low (25 ppm) or high (225 ppm) levels of dietary DL-alpha-tocopheryl acetate (VE-AC) from 1 day of age. In both trials, rates of weight gain were depressed between days 5 and 7 post-inoculation (PI) and were not influenced by the level of dietary VE-AC. Plasma AT was consistently depressed at 5 and 7 days PI in chickens consuming either level of dietary VE-AC. The pattern and degree of plasma AT depression correlated with those of plasma carotenoids. Plasma levels of NO2- + NO3- were significantly increased at 5 and 7 days PI. In trial 1, the average increase during that period was not as high in chicks consuming 225 ppm VE-AC, but in trial 2, diet had no effect on the degree of increase. Also, there were no consistent effects of dietary VE-AC on lesion scores or amount of oocysts shed. These results are in general accord with findings of earlier experiments, and we conclude that feeding high levels of VE-AC to broiler chicks from 1 day of age is not effective in mitigating the pathology, including weight gain depression and development of mucosal lesions, during E. maxima infections or in modifying immune response events associated with phagocytosis as indexed by plasma NO2- + NO3-. The likely basis for the ineffectiveness of feeding this fat-soluble form of vitamin E is that it is malabsorbed during E. maxima infection in the same manner as carotenoids and becomes less biologically available to infected tissues during the acute phase of infection.

The effect of dietary protein content and feeding level on the rate of protein deposition and energy utilization in growing Iberian pigs from 15 to 50 kg body weight.

The effects of dietary protein content and feeding level on the utilization of metabolizable energy (ME) and on the rates of gain, protein and fat deposition have been studied in seventy-two Iberian pigs growing from 15 to 50 kg body weight (BW) by means of comparative slaughter experiments. The animals were fed on six diets providing 223, 192, 175, 156, 129 and 101 g crude ideal protein ( CP)/kg DM and 14.64, 14.14, 14.37, 14.80, 15.36 and 15.53 MJ ME/kg DM respectively. Each diet was offered at three levels of feeding: 0.60, 0.80 and 0.95xad libitum intake. Protein deposition (PD) increased significantly (P<0.01) with each decrease in dietary CP content and reached a maximum value (74.0 g) when the diet providing 129 g CP/kg DM (6.86 g digestible ideal protein/MJ ME) was offered at the highest feeding level. This feeding regimen resulted in average values for live-weight gain and retained energy (RE) of 559 g/d and 10.9 MJ/d respectively. RE increased significantly (P<0.001) from 480 to 626 kJ/kg BW0.75 with each decrease in dietary CP content from 192 to 129 g/kg DM. Raising the level of feed intake led to significant linear increases in PD and RE irrespective of the diet fed (P<0.001). When diets approaching an adequate supply of CP were given, the net efficiency of use of ME for growth (kw) and the maintenance energy requirements were 58.2 % and 422 kJ/kg BW0.75 per d respectively.

The effect of dietary protein content and feeding level on the rate of protein deposition and energy utilization in growing Iberian pigs from 15 to 50kg body weight

The effects of dietary protein content and feeding level on the utilization of metabolizable energy (ME) and on the rates of gain, protein and fat deposition have been studied in seventy-two Iberian pigs growing from 15 to 50 kg body weight (BW) by means of comparative slaughter experiments. The animals were fed on six diets providing 223, 192, 175, 156, 129 and 101 g crude ideal protein (N×6·25; CP)/kg DM and 14·64, 14·14, 14·37, 14·80, 15·36 and 15·53 MJ ME/kg DM respectively. Each diet was offered at three levels of feeding: 0·60, 0·80 and 0·95×ad libitum intake. Protein deposition (PD) increased significantly (P&lt;0·01) with each decrease in dietary CP content and reached a maximum value (74·0 g) when the diet providing 129 g CP/kg DM (6·86 g digestible ideal protein/MJ ME) was offered at the highest feeding level. This feeding regimen resulted in average values for live-weight gain and retained energy (RE) of 559 g/d and 10·9 MJ/d respectively. RE increased significantly (P&lt;0·001) from 480 to 626 kJ/kg BW0·75 with each decrease in dietary CP content from 192 to 129 g/kg DM. Raising the level of feed intake led to significant linear increases in PD and RE irrespective of the diet fed (P&lt;0·001). When diets approaching an adequate supply of CP were given, the net efficiency of use of ME for growth (kw) and the maintenance energy requirements were 58·2 % and 422 kJ/kg BW0·75 per d respectively.

Small intestine growth and morphometry in piglets weaned at 7 days of age. effects of level of energy intake.

Two trials involving a total of 56 pigs were conducted to examine the effects of weaning at 7 d of age (trial 1) and of energy intake level and length of post-weaning underfeeding period (trial 2) on small intestinal (SI) development and morphometry. At 3 d after weaning, weight of the SI and mucosa (g/kg body weight) and villous height along SI were reduced by 20, 36 and 41%, respectively, compared to the day of weaning. Intestinal morphometrical changes are dependent on SI site and days post-weaning. Villous atrophy on d 3 and recovery on d 14 post-weaning were greater and occurred earlier in the proximal than in the medial and distal SI. Villous height was dependent on the level of energy intake which explains 56% of the variations in proximal SI villous height in weaned pigs and 73% when data of the sow-reared pigs were included in the analysis. Moreover, after 4 d of refeeding, underfed piglets showed similar villous characteristics to piglets fed a continuously high feeding level after weaning stressing that capacities of intestinal restoration were not affected by the length of the post-weaning underfeeding period. Overall, the present results suggest a spatial and temporal effect of weaning on villous atrophy and recovery, and that the level of energy intake is a major factor accounting for the post-weaning villous height.

A comparison of Friesian-Holstein, Piemontese×Friesian-Holstein and Romagnola×Friesian-Holstein steers for beef production and carcass traits

Recently the Italian Piemontese and Romagnola beef breeds have been imported into Ireland. The objective of this study was to evaluate the progeny of these breeds from Friesian-Holstein dairy cows for beef production. A total of 120 spring-born steers comprised of 40 Friesian-Holsteins (FR), 40 Piemontese×Friesian-Holsteins (PM) and 40 Romagnola×Friesians-Holsteins (RO), born in 2 consecutive years, were reared from calfhood to slaughter at ∼2 years of age. Calves were artificially reared indoors and spent their first summer at pasture towards the end of which they were castrated. They were housed during the first winter and subsequently spent their second summer at pasture. At the start of the second winter they were assigned to a 3 (FR, PM, RO breed types)×2 (low and high feeding levels)×2 (short and extended finishing periods) factorial experiment. The low (L) and high (H) feeding levels were 3 and 6 kg concentrates per head daily, respectively, with grass silage ad libitum. The short (S) and extended (E) finishing periods were 124 and 207 days, respectively. After slaughter, the pistola hind quarter was separated into subcutaneous and intermuscular fats, bone and muscle. For the breed types as listed, mean values for carcass weight per day from arrival, kill-out proportion, carcass conformation score and carcass fat score were 434, 435, and 453 (S.E.D. 7.6) g, 519, 547 and 538 (S.E.D. 3.7) g/kg, 2.1, 2.9 and 2.9 (S.E.D. 0.12), and 4.0, 3.4 and 3.8 (S.E.D. 0.11), respectively. For FR, PM and RO, pistola weight as a proportion of carcass side weight was 447, 462, and 466 (S.E.D. 2.5) g/kg, pistola muscle proportion was 642, 716 and 687 (S.E.D. 4.1) g/kg, and pistola fat proportion was 165, 115 and 137 (S.E.D. 4.0) g/kg, respectively. Compared with L, the H feeding level increased carcass weight and improved carcass conformation but otherwise had few effects on carcass traits. Compared with S, the E finishing period increased carcass weight and all measures of carcass fatness. Allometric growth coefficients relative to carcass side weight for the hind quarter, the distal pelvic limb, the lumbar joint and the ribs joint were all <1.0, while the fore quarter and the proximal pelvic limb had coefficients >1.0. It is concluded that the Piemontese and Romagnola beef breeds are suitable for crossing on Friesian-Holstein dairy cows and the progeny are suited to Irish steer beef production systems. Productivity and carcass merit of these beef crosses are superior to those of Friesian-Holsteins. While live and carcass growth rates were higher for RO than PM, both had similar estimated muscle growth rates.

Rearing Black Bengal Goat under Semi-Intensive Management 1. Physiological and Reproductive Performances

Ninety pre-puberal (6-7 months) female and 15 pre-puberal male Black Bengal goats were collected on the basis of their phenotypic characteristics from different parts of Bangladesh. Goats were reared under semi-intensive management, in permanent house. The animals were vaccinated against Peste Des Petits Ruminants (PPR), drenched with anthelmentics and deeped in 0.5% Melathion solution. They were allowed to graze 6-7 h along with supplemental concentrate and green forages. Concentrates were supplied either 200-300 g/d (low level feeding) or quantity that supply NRC (1981) recommended nutrient (high level of feeding). Different physiological, productive and reproductive characteristics of the breed were recorded. At noon (temperature=95 ° F and light intensity=60480 LUX) rectal temperature and respiration rate of adult male and female increased from 100.8 to 104.8 ° F and 35 to 115 breath/min, indicated a heat stress situation. Young female attain puberty at an average age and weight of 7.2±0.18 months and 8.89±0.33 kg respectively. Mean age and weight at 1st kidding were 13.5±0.49 months and 15.3±0.44 kg respectively. It required 1.24- 1.68 services per conception with an average gestation length of 146 days. At low level of feeding the postpartum estrus interval was 37±2.6 days, which reduced (p<0.05) with high feeding level to 21±6.9 days. Kidding interval also reduced (p<0.05) from 192 d at low feeding level to 177 d at high feeding level. On an average there were two kiddings/doe/year. Average litter sizes in the 1st, 2nd, 3rd and 4th parity were 1.29, 1.71, 1.87 and 2.17 respectively. Birth weights of male and female kids were 1.24 and 1.20 kg respectively, which increased (p<0.05) with better feeding. Although kid mortality was affected (p<0.05) by dam's weight at kidding, birth weight of kid, milk yield of dam, parity of kidding, season of birth, but pre-netal dam's nutrition found to be the most important factor. Kid mortality reduced from 35% at low level of feeding to 6.5% at high level of feeding of dam during gestation. Apparently, this was due to high (p<0.05) average daily milk yield (334 vs. 556 g/d) and heavier and stronger kid at birth at high feeding level. (Asian-Aust. J. Anim. Sci. 2002. Vol 15, No. 4 : 477-484)

Polyethylene glycol, determined by near-infrared reflectance spectroscopy, as a marker of fecal output in goats.

We report the application of NIR spectroscopy to determine the fecal concentration of poly(ethylene glycol) (PEG, MW 6000) used as an external marker of fecal output in goats. Calibration was carried out, using the modified partial least-squares method (MPLS), combining all wavelengths in the 1100-2500 nm range, with high linearity (R2 = 0.99). In goats fed at maintenance level, the recovery of PEG in feces was complete, and the estimation of fecal output was accurate, when a moderate dose of PEG was given (20 g/d). A higher dose of PEG (40 g/d) was associated with underestimation of fecal output, probably because PEG interacted with water metabolism. Using PEG and its NIRS-aided analysis to determine fecal output is accurate, simple, and cheap. However, the feasibility of this new method must be verified in goats feeding on tannin-containing diets, and in goats at high feeding level.

Effect of feeding level on milk production, body weight change, feed conversion and postpartum oestrus of crossbred lactating cows in tropical conditions

Responses to high (H), medium (M) and low (L) feeding levels on milk yield, reproduction and body weight (BW) were evaluated on 30 multiparous crossbred F1 cows (Holstein Friesian×Vietnamese Local Yellow) in lactation week 9–24, divided into two periods of 8 weeks each. The cows were blocked and randomly divided into five groups with feeding levels of H–H, H–L, L–H, L–L and M–M. The medium level was based on the NRC standard (Nutrient Requirements of Dairy Cattle, National Academy Press Washington, DC, 1988), the high level being 10% above and the low 10% under the standard. The cows were fed a constant amount of grass forage, brewer’s grains and varying amounts of concentrates depending on feeding level, body weight and milk yield of each cow at the start of the experiment. The amount of concentrates to each cow was constant during each 8-week period. Mean daily milk yield was 10.43, 9.81, 9.38, 8.74 and 9.88 kg and body weight changes 29, 12, 14, −3 and 19 kg for H–H, H–L, L–H, L–L and M–M cows, respectively. The milk yield and body weight changes were significantly different between feeding levels ( P<0.05) but no significant effects of feeding level on milk composition were found. A strong tendency ( P=0.09) to prolonged interval to first postpartum oestrus was observed on the low feeding level.

High Dietary Lipids Induce Liver Glucose-6-Phosphatase Expression in Rainbow Trout (Oncorhynchus mykiss)

To contribute to the understanding of the mechanisms involved in poor metabolic utilization of dietary carbohydrates by rainbow trout (Oncorhynchus mykiss), we explored in this study the effects of dietary lipids on the regulation of two hepatic key enzymes, i.e., glucokinase (GK, first enzyme of the glycolytic pathway) and glucose-6-phosphatase (G6Pase, last enzyme of the gluconeogenesis). Two groups of juvenile trout were pair-fed for 8 wk either a low (10%) or a high (25%) level of dietary lipids supplied as fish oil; the pair-feeding technique was adopted to vary fat intake while keeping the protein and carbohydrate intakes more or less constant. Fish fed the high level of dietary lipids had inefficient control of glycemia compared with fish fed the low level of lipids. Levels of dietary lipids did not affect GK activity even though there was a small increase of GK mRNA level at 3 h after feeding high levels of lipids. By contrast, the high level of dietary lipids significantly increased G6Pase mRNA expression at 3, 6 and 12 h and enzyme activity at 6 h after food consumption. Thus, these data suggest that poor dietary carbohydrate utilization in rainbow trout may be related at least in part to increased hepatic glucose production under conditions of high dietary fat intake.

Induction of pseudopterosin biosynthesis in the gorgonian Pseudopterogorgia elisabethae.

A number of biological and physical stimuli have been evaluated as inducers of pseudopterosin biosynthesis in the sea whip Pseudopterogorgia elisabethae. Data indicate that the production of pseudopterosins can be significantly increased in response to high levels of predation by the mollusk Cyphoma gibbosum and in response to decreased levels of UV/visible radiation. High levels of feeding by Chaetodon capistratus and an artificial wounding of the sea whip did not result in increased pseudopterosin levels.

Lactation Performance of German Fawn Goat in Relation to Feeding Level and Dietary Protein Protection

Effects of high and low levels of feeding with or without protected protein on the performance of lactating goats were studied. Twenty four German Fawn goats either from 1st (43.37±3.937 kg and 2 year old) or 3rd 62.64±6.783 kg and 4-5 year old) parity were used for the trial. Feeding levels were 7.2 (I) and 5.2 (II) MJ ME/litre of milk of 3.5% fat in addition to that of the maintenance allowance. At each feeding level, diet had either unprotected (U) or formaldehyde protected (P) soya-meal. Thus, four diets were IU, IP, IIU and IIP, having six animals in each. The diets were composed of hay and pellet (10:4:1 of beet pulp : barley : soya-meal). Effect of feeding level, protein protection, parity, health status and kid number on intake, milk yield, milk composition, growth rate of goats were recorded across the 21 weeks of study. High feeding level resulted increase (p<0.001) in estimated metabolizable energy (ME) and metabolizable protein (MP) availability. Dietary inclusion of protected soya-meal increased (p<0.001) the estimated MP but not the ME availability. Animals in 1st parity ate more (p<0.001) DM (111 vs. 102 g/kg W 0.75 /d) than those in 3rd parity. Animals with twin kids (110 g/kg W 0.75 /d) had higher (p<0.001) DM intake than those with single kid (102 g/kg W 0.75 /d). Fat (4%) corrected milk (FCM) yield was not effected by high (1,924 g/d) or low (1,927 g/d) feeding level but increased (p<0.001) with protected (2,166 g/d) compared with unprotected (1,703 g/d) soya-meal. FCM yield for four dietary combinations were 1,806, 2,078, 1,600 and 2,254 g/d for diets IU, IP, IIU and IIP, respectively. For unit increase (g) in estimated MP availability relative to ME (MJ) intake, FCM yield increased 1,418(±275.6) g daily (r 2 =0.58; p<0.001). Milk fat (3.14 vs. 3.54%; p<0.001) and protein (2.94 vs. 3.04% p<0.05) contents were lower at high than the low feeding level. Protected protein increased (p<0.001) the fat, lactose and net energy (NE) content of milk. Milk urea concentration of 175, 183, 192 and 204 mg/l for diets IU, IP, IIU and IIP, respectively indicated lower RDP content of these diets. The RDP contents were 6.97, 6.70, 7.30 and 6.83 g/MJ of ME for diets IU, IP, IIU and IIP, respectively. Live weight change over the experimental period were 41, 6, 17 and 19 g/d. Absence of any positive response of high feeding was probably due to inefficient rumen fermentation resulting from inadequate RDP supply. Protected protein improved production performance apparently by increasing MP:ME ratio in the absorbed nutrient. (Asian-Aust. J. Anim. Sci. 2002. Vol 15, No. 2 : 222-237)