High Feeding Level Research Articles

Dietary formulation with meat and bone meal on a total versus a digestible or bioavailable amino acid basis

The digestibility and bioavailability of amino acids (AA) in meat and bone meals (MBM) may vary greatly due to different processing conditions. In the present study, two experiments were conducted to evaluate formulation of diets containing high or low quality MBM on a total AA basis vs a digestible or bioavailable AA basis compared to a corn-soybean meal control diet. Lysine, methionine, and cystine digestibilities (precision-fed cecectomized rooster assay) were 92, 91, and 71%, respectively, for high quality MBM and were 71, 83, and 31%, respectively, for the low quality MBM. Bioavailability values (slope-ratio chick growth assay) for TSAA in the two MBM were approximately 15 percentage units lower than the digestibility values. Male crossbred chicks were fed a 20% CP corn-SBM diet or corn-SBM diets containing 10 or 20% high or low quality MBM that were formulated to be equal in total, digestible, or bioavailable AA to the corn-SBM diet. All diets contained 3,200 kcal of TMEn/kg, 1.4% Ca, and 0.7% nonphytate P and were fed to chicks from 8 to 22 d posthatching. Growth performance of chicks fed 10 or 20% high or low quality MBM on a total AA basis was lower (P < 0.05) than that of chicks fed the corn-SBM diet. Growth of chicks fed 10% low quality MBM or 10 or 20% high quality MBM on a digestible or bioavailable basis was equivalent to that of chicks fed the corn-SBM diet; however, dietary inclusion of 20% low quality MBM depressed growth (P < 0.05) even on a digestible or bioavailable AA basis. Further supplementation of the latter diet with additional AA yielded growth that was similar to the corn-SBM control diet. The results indicated that formulation of diets containing MBM on a digestible or bioavailable AA basis is superior to formulation on a total AA basis. However, feeding high levels of a low quality MBM may require additional AA supplementation to obtain maximum chick growth.

Effects of temperature on anti-predator behaviour in the guppy,Poecilia reticulata

Warmer environmental temperatures are likely to increase the frequency of predator–prey interactions in ectothermic animals, and therefore might be expected to influence anti-predator behaviour. In a first experiment, groups of recently fed guppies, placed in a novel environment, schooled significantly more closely at 26° than at 22°C. Changes in two of three measures of schooling tendency over time indicated that aggregation increased during the trial periods, probably as a result of increased familiarity within the experimental groups. In a second experiment, pairs of female guppies were tested at 22° and 26°C, with and without predation threat from a confined cichlid. From multifactor analysis of 18 behaviour types, temperature was shown to affect behavioural time budgets profoundly, particularly in the presence of the predator. At the higher temperature, a shift occurred from inactive anti-predator behaviours and minimal foraging activity towards active predator inspection-related behaviours and a much higher level of feeding. Guppies in the warmer water might have been physically able to school more closely as a result of faster swimming ability, or might have used temperature as a cue indicating higher potential predation risk, and aggregated accordingly. The use of temperature as a source of information about the biotic environment is discussed.

The influence of vitamin A on the utilization and amelioration of toxicity of cholecalciferol, 25-hydroxycholecalciferol, and 1,25 dihydroxycholecalciferol in young broiler chickens

Three experiments were conducted to determine the influence of vitamin A on the utilization and amelioration of toxicity of cholecalciferol (vitamin D3), 25-hydroxycholecalciferol [25-(OH)D3], and 1,25-dihydroxycholecalciferol [1,25-(OH)2D3] in young broiler chicks. Two levels of vitamin A (1,500 and 45,000 IU/kg or 450 and 13,500 microg) were fed in all experiments. In Experiment 1, chicks were fed six levels of vitamin D3 (0, 5, 10, 20, 40, and 80 microg/kg). High dietary vitamin A decreased bone ash (P < 0.001), and increased the incidence of rickets (P < or = 0.02). Linear and quadratic responses to vitamin D3 levels were significant (P < 0.01) for body weight, bone ash, incidence and severity of rickets, and plasma calcium. In Experiment 2, six levels of 25-(OH)D3 (0, 5, 10, 20, 40, and 80 microg/kg) were added to the basal diet. Adding 25-(OH)D3 increased (P < 0.001) body weight, bone ash, and plasma calcium, and decreased rickets and plasma vitamin A. Adding 25-(OH)D3 overcame the reduction in bone ash produced by high dietary vitamin A showing a significant (P < 0.02) interaction. In Experiment 3, six levels of 1,25-(OH)2D3 (0, 2, 4, 8, 16, and 32 microg/kg) were added to the basal diet. High dietary vitamin A increased (P < 0.01) the incidence and severity of rickets. Adding 1,25-(OH)2D3 increased (P < 0.01) body weight, bone ash, plasma calcium, and reduced rickets and plasma and liver vitamin A. Adding 1,25-(OH)2D3 overcame the reduction in bone ash, and the increase in rickets produced by high vitamin A was significant (P < or = 0.05). These results indicate that high dietary vitamin A (45,000 IU/kg) interferes with the utilization of vitamin D3, 25-(OH)D3 and 1,25-(OH)2D3, increasing the requirement for each of them. Moreover, 45,000 IU/kg of dietary vitamin A ameliorated the potential toxic effects of feeding high levels of vitamin D3, 25-(OH)D3 and 1,25-(OH)2D3 to young broiler chickens. Further work is necessary to find the minimum levels of these vitamins needed to cause these effects.

Relationship between ration size and dietary protein level varying at the expense of carbohydrate and lipid in triploid brown trout fry, Salmo trutta

A feeding trial was conducted with brown trout fry (initial body weight: 2 g) in order to estimate the best combination of feeding level and protein content. The factorial design consisted of feeding four dietary protein levels (47, 53, 58 and 63%) at four ration sizes (70, 85, 100 and 115% of a previous empirical reference). Fish were weighed at 21 and 42 days and at the end of the experiment that lasted 57 days. Two replicates were used for each protein×ration level combination. Diets had approximately the same energy level (about 18.5 MJ DE) and contained the same protein source with varying carbohydrate: fat ratio. Protein efficiency, estimated by productive protein value, was improved by low dietary protein level and feed restriction. Body composition was slightly but significantly affected by diet composition, with body lipid content decreasing with high dietary protein. The lowest ration (70%), even with the highest protein content, as well as the lowest protein content (47%), even with the highest feeding level, did not allow maximal growth which was nevertheless achieved with several protein content×ration size combinations. Combinations which yielded equivalent growth rates did not give the same feed efficiency, this criterion being best with 58 or 63% protein diets fed at 85% of the previous reference. Protein requirement was found to depend on feeding level; absolute requirement was estimated to be between 10 and 13 g balanced protein/kg body mass/day, while calculated absolute energy requirement was between 330 and 450 kJ DE/kg body mass/day. In these conditions, specific growth rate was of 2.7%. When compared to other fishes growing at the same rate, the absolute requirement of brown trout for protein appears to be rather low.

The influence of diet before and after calving on the food intake, production and health of primiparous cows, with special reference to sole haemorrhages

AbstractSixty-five primiparous cows were used in two experiments to study the effects of feeding high or low levels of concentrate during the last 2 to 3 weeks before calving on performance in early lactation. During early lactation (until 12 or 16 weeks after calving) all the 23 cows in experiment 1 were given the same diet. In experiment 2, the 42 cows were given diets with a ratio of concentrate/forage of either 60:40 or 40: 60, each providing the same energy level.The food intake of almost all the cows decreased in the few days before calving but the decrease was less pronounced among those on the low concentrate level before calving. The average daily food intake during the calving week gave a metabolizable energy intake about 30 MJ higher on the high compared with the low feeding level. The level of feeding before calving had no effect on the cows' food intake after calving, or on their milk yield, health and fertility, or on scores for udder oedema and sole haemorrhages. The high level offeeding before calving was associated with significantly higher concentrations of insulin and lower concentrations of free fatty acids in the calving week of lactation but the level offeeding either before or after calving had no effect on these concentrations in the 8th week of lactation. The feeding of a high ratio of concentrate/forage after calving was associated with a significantly lower milk fat content. It can be concluded that the concentrate/forage ratio at calving does not seem to have any significance for the performance after calving.

The effects of energy intake on responses to metabolisable protein in dairy cows

Previous work (Metcalfet al1996) has suggested that, even for cows when ME and MP supplies were balanced, the relationship between MP intake and net protein output at higher levels of feeding and production differs from that assumed in the MP system. This experiment was designed to test the concept that the efficiency of MP use for milk protein secretion is limited when metabolisable energy (ME) is limiting.

The effects of energy intake on responses to metabolisable protein in dairy cows

Previous work (Metcalfet al1996) has suggested that, even for cows when ME and MP supplies were balanced, the relationship between MP intake and net protein output at higher levels of feeding and production differs from that assumed in the MP system. This experiment was designed to test the concept that the efficiency of MP use for milk protein secretion is limited when metabolisable energy (ME) is limiting.

Oxidation of substrates and lipogenesis in pigs ( Sus scrofa), mink ( Mustela vison) and rats ( Ratus norvegicus)

Data from experiments with 25 growing pigs at high feeding level, with 12 adult mink on a varied energy supply and with 36 rats on a maintenance level were used in a biological model of nutrient oxidation, lipogenesis and retention at the whole body level. Nutrient oxidation was calculated from gas-exchange measurements in respiration chambers working according to indirect calorimetry principles. Lipogenesis and nutrient retent retention were measured by means of carbon and nitrogen balances, in accordance with the demonstrated model. The results demonstrated that growing pigs had a high level of protein retention and low protein oxidation. Digested carbohydrates were oxidates were oxidized or used for lipogenesis. Oxidation of carbohydrate was the main energy source, while lipogenesis was the main source of fat retention. Independent of dietary fat level, pigs did not oxidize fat but used all dietary fat for body fat retention. The mink, being fed with high protein and fat levels but only a small amount of carbohydrate, use protein and fat as their main energy sources. Rats fed near-maintenance level used dietary carbohydrate as a main substrate for oxidation. It was demonstrated that the present model of nutrient oxidation, lipogenesis and retention in different animal species and at different dietary composition can be quantified by means of indirect calorimetry and measurements of carbon and nitrogen balances.

Promising tropical grasses and legumes as feed resources in Central Tanzania III: Effect of feeding level on digestibility and voluntary intake of four grasses by sheep

An experiment was conducted to study the effect of increasing feeding level on digestibility and voluntary intake of four high yielding grasses cut at 6 and 10 weeks. The grasses were fed to Blackhead Persian rams (mean age = 72 weeks; mean weight = 30 kg) at levels of 600, 900, 1200, 1500 and 1800 g of hay per day in a split plot design. The grasses were Cenchrus ciliaris cv. Biloela (CCB), C. ciliaris cv. Gayndah (CCG), Panicum coloratum cv. Bambatsi (PCB) and Chloris gayana cv. Mpwapwa (CGM). In vivo organic matter (OM) digestibility was on average 60%. Among the species compared, CCB and PCB had lower OM digestibility, by 3 units, than CCG and CGM ( P < 0.05), but CGM had lower intakes ( P < 0.05) than the other species by approximately 20%. Samples taken at 10 weeks regrowth had higher neutral detergent fibre (NDF) and lignin contents and lower protein contents and in vitro organic matter digestibility compared to the 6-week cuts. Intake of OM, but not of NDF was also lower ( P < 0.05) for the 10-week cut. The sheep consumed the grasses selectively in favour of the more nutritious parts when offered excess feed. With higher feeding levels, OM digestibility, but not NDF digestibility, was significantly improved ( P < 0.05). Voluntary intakes of all species and stages were also improved by increasing feeding levels ( P < 0.05). The lowest levels of feeding, allowing maximum intakes of the hays, varied between species and stages of maturity. These feeding levels ranged from 900–1500 g of hay per day with refusals between 15.3–50.8% for PCB (6 weeks) and CGM (10 weeks), respectively. From calculations of optimal feeding levels to attain maximum daily nutrient uptake by producing sheep, we recommend early harvesting and feeding of the grasses at levels allowing refusals of at least 30%.

The effect of feeding high levels of fish oil and additional vitamin E on intake, milk yield, composition and fatty acid content in high yielding dairy cows

The COMA report on The Nutritional Aspects of Cardiovascular Disease (1994) recommended that the intake of long chain n-3 polyunsaturated fatty acids, including eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), by the UK population should double. EPA and DHA in the human diet are derived principally from oily fish. The aim of this experiment was to determine the effect of increasing levels of fish oil in the diet at two levels of vitamin E supplementation, on intake, milk production, the extent of uptake of EPA and DHA into milk fat at levels exceeding those investigated to date, and the effect of a dietary supplement of vitamin E on fatty acid content.

The effect of feeding high levels of fish oil and additional vitamin E on intake, milk yield, composition and fatty acid content in high yielding dairy cows

The COMA report on The Nutritional Aspects of Cardiovascular Disease (1994) recommended that the intake of long chain n-3 polyunsaturated fatty acids, including eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), by the UK population should double. EPA and DHA in the human diet are derived principally from oily fish. The aim of this experiment was to determine the effect of increasing levels of fish oil in the diet at two levels of vitamin E supplementation, on intake, milk production, the extent of uptake of EPA and DHA into milk fat at levels exceeding those investigated to date, and the effect of a dietary supplement of vitamin E on fatty acid content.

Impact of high level of intensive feeding of two-year-old carp (Cyprinus carpio L.)-with feeds differing in fat and carbohydrate composition-on the levels of cortisol, glucose, triglycerides in the blood and on the body weight increments

Intensive culture of two-year-old carp, using a diet with elevated content of fats or carbohydrates causes highly statistically significant increase of cortisol and triglycerides in the blood of both feeding groups and statistically significant decrease in glucose level in the fish fed with high-carbohydrate diet.

Muscle fatty acid composition and oxidative stress indices of Arctic charr, Salvelinus alpinus (L.), in relation to dietary polyunsaturated fatty acid levels and temperature

The influence of feeding high levels of polyunsaturated fatty acids (PUFA) on muscle fatty acid composition and indices of oxidative damage was examined in Arctic charr, Salvelinus alpinus (L.). All diets contained 100 g kg−1 lipid of dry weight. Two diets contained marine fish oils giving a PUFA level of 250 g kg−1 and 500 g kg−1 of lipid. The remaining two diets contained vegetable oils high in either 18:2n-6 or 18:3n-3, giving a PUFA level of more than 500 g kg−1 of dietary lipid. The charr were maintained at 8°C until their weight doubled, and were then transferred to 0.8°C for 30 days. Growth was similar in all groups. The fatty acid compositions of muscle were influenced by dietary PUFA but were less diverse than those of the diets. The overall pattern of fatty acid compositions indicated preferential desaturation and elongation of n-3 PUFA coupled with selective oxidation of 18:2n-6. Total n-3 PUFA content in TAG was always lowered compared with the diet, suggesting a specific mechanism for the removal of these fatty acids. Subjecting the fish to low temperature increased PUFA content in muscle of charr fed the 250 g kg−1 marine n-3 PUFA diet, but had no effect on the other treatments. For fish at 8°C, no significant differences were found between groups in terms of haematocrit, plasma alanine aminotransferase (ALAT), and plasma and muscle thiobarbituric acid reactive substances (TBARS), although there was a tendency towards increased levels of TBARS in the group receiving 500 g kg−1 marine n-3 PUFA of lipid. Subjecting the muscle to forced oxidative conditions resulted in increases in TBARS in all groups, particularly those fed 500 g kg−1 marine n-3 PUFA. Lowering the environmental temperature corresponded with a further increase in the plasma ALAT and muscle TBARS in this group. It is concluded that feeding diets containing high levels of long-chain n-3 PUFA may be detrimental to the fish's health and flesh quality, particularly at low environmental temperatures.

Effect of varying ambient temperature and porcine somatotropin treatment in pigs on feed intake and energy balance traits

Effects of feeding levels (64 g kg −0.75 d −1 = low; 87 g kg −0.75 = high) and recombinant porcine somatotropin (rpST) on energy balance traits of castrate pigs (approximately 53 kg live weight) in 8 groups of 12 each were studied in a 2 × 2 factorial arrangement. In two consecutive balance periods of 12 d each, ambient temperatures were changed 3 °C each day at 0900 in a stepwise fashion from 23 to 8 °C and then upward from 8 to 23 °C. Four groups received 4 mg of rpST per day per animal and four groups received a placebo. Control high feeding level pigs were pair-fed with ad libitum fed rpST-treated pigs. Pigs treated with rpST showed an increased heat production of 65 kJ kg −0.75 d −1 and maintenance requirement (MEm) of 75 kJ kg −0.75 d −1 compared to control. Protein deposition was 130 and 176 g d −1, and fat deposition 210 and 134 g d −1 in control and rpST-treated pigs, respectively. Feed:gain ratio improved from 2.92 to 2.26 and rate of gain from 665 to 840 g d −1 with rpST. High feeding level pigs had increased heat production (+97 kJ kg −0.75) and retained more energy (+220 kJ kg −0.75 d −1). They also showed increased protein and fat depositions, and rate of gain. Pigs at optimal and suboptimal temperatures showed similar metabolic responses to rpST.

Effect of feeding level on feed losses and feed utilization of soya and fish meal diets in Colossoma macropomum (Cuvier)

Juvenile, 1-g Colossoma macropomum (Cuvier) were fed two different diets: one with fish meal and another with soya meal as the main dietary protein source. Both diets were provided at ad libitum feeding level, and at two restricted feeding levels of ∼ 80% and 60% of the ad libitum level. The experiment was performed in 30 aquaria, each stocked with 12 fish. For each treatment (two diets X three feeding levels), there were five replicates. Fish were fed three times daily at 0900, 1300 and 1700 h. At sampling days (days 14, 29, 44) in each aquarium in one of these feedings, chromic-oxide-marked feed was used. Shortly after the last meal, fish were weighed and four fish were taken from each aquarium for determination of the chromic oxide content in their digestive tract. Fish fed the fish meal diet attained a higher weight but had a lower body protein content. At the ad libitum feeding level, feed intake of the fish meal diet was higher, but feed and protein utilization efficiency were lower than with the soya diet. However, statistical analysis of the data of both the ad libitum and the two restricted feeding levels revealed that the reduced voluntary feed intake of the soya diet was the cause of its better utilization with ad libitum feeding. There is no evidence that soya protein is more freely available than fish meal protein. The chromic oxide data showed that 15 min after feeding, all of the feed (99.8%) could be traced back in fish fed the lowest feeding level, while at the ad libitum feeding level the recovery was only 72%. These data confirmed the hypothesis that at high feeding levels, considerable amounts of feed remain uneaten. Feed losses were not significantly different between the two diets. The chromic oxide recovery data of the 0900 h and 1300 h feedings showed that the feed passage rate in the digestive tract was similar for the three different feeding levels. Due to the high feed losses at high feeding levels, the relation between feed ration and feed utilization is determined mainly by the percentage of feed losses at the different feed rations.

The effect of nutrition on fibre growth in the alpaca

AbstractTwelve adult male alpacas were given either 0·67 (low) or 2·0 (high) × assumed maintenance requirements for a period of 6 weeks after which time each was transferred to the alternative level of nutrition for a further 6 weeks. Fibre samples were taken from two 10-cm2 areas on the mid-side position of each animal at 2, 6, 8 and 12 weeks, and measurements of fibre weight, yield (clean fibre weight/raw fibre weight), fibre diameter and fibre length made on the samples collected at weeks 6 and 12. The higher level of feeding resulted in higher clean fibre weight (low = 0·42 (s.e. 0·03); high = 0·53 (s.e. 0·04)mg/cm2 per day, P &lt; 0·001) and fibre growth rate (low = 186 (s.e. 10); high = 223 (s.e. 14) yon/day, P &lt; 0·05). Changes in yield (low = 0·917 (s.e. 0·006); high = 0·929 (s.e. 0·009)) and mean fibre diameter (low = 31·4 (s.e. 1·9); high = 32·1 (s.e. 1.6) \xm) were not statistically significant. Calculations showed that the increased weight of fibre attributed to the higher level of nutrition could be explained in terms of the observed increases in fibre-length and diameter but that, unlike the sheep in which the ratio fibre length: diameter remains relatively constant under varying nutritional regimes, the effect of nutrition in the alpaca has a proportionally larger effect on fibre length than on fibre diameter.

Effects of food supply on size at first maturity, fecundity and growth of hybrid tilapia, Oreochromis niloticus (L.) x Oreochromis aureus (Steindachner), in outdoor concrete tanks in Saudi Arabia

The effects of four levels of food supply (0.5%, 1%, 2% and 3% body weight daily) were investigated on some reproductive traits and growth of hybrid tilapia in outdoor concrete tanks. Fast-growing fish matured early in the season (March), but spawning started late in May. Smallest size of males and females at first maturity was 8.1 cm. Fish size at maturity appears to be influenced by the feeding level, which affects the growth of fish. For both sexes, no significant difference was found in gonadosomatic index (GSI) among different treatments. Mean percentage of mature fish decreased with decreasing food supply and was found to be significantly different between fishes fed at 3% (46%) and 0.5% (28%) body weight. Fecundity increased with increased feeding levels, although significant differences were found only between 3% and other feeding rates (0.5–2.0%). The fecundity per g female was higher at the lower ration levels (0.5% and 1%) than at the higher feeding levels. Egg quality, with respect to egg size, hatchability. fry length and weight, was not affected by the feeding rates. Final mean weight and food conversion ratios were significantly influenced by feeding rates. Higher increase in ovary weight with increasing body weight of mature females fed at 0.5% body weight than fishes receiving higher food levels suggests that in these fish, more food resources are diverted towards gonad building than to somatic growth.

Heart rate and respiratory adjustments during work of increasing intensity in Hinterwaelder and Zebu oxen

AbstractHeart rate, ventilation measurements and gas exchange were studied in seven Hinterwaelder (Bos taurus) (494 (s.e. 16) kg) and five zebu (Bos indicusj oxen (516 (s.e. 60) kg), while the animals were standing, walking and pulling different loads. During standing, the heart rate, respiration rate, ventilation volume per min, total carbon dioxide production, total oxygen consumption and oxygen consumption per heart beat were lower in the zebu group than in the Hinterwaelder group (P &lt; 0·05). The higher values for the Hinterwaelder were probably due to their higher metabolic rate, because of their younger age, higher level of feeding and better quality diet. The adaptation of gas exchange to higher work loads was achieved mainly by higher ventilation volumes. The composition of the expired air changed minimally. At similar levels of draught power output, the total energy expenditure minus energy expenditure of walking of the zebu oxen was lower than that of the Hinterwaelder oxen (P &lt; 0·02). On the other hand at similar levels of heat production, the heart rate and ventilation volume per min did not differ significantly between the two breeds (P &gt; 0·05). In spite of the differences in environment, feeding level and draught efficiency, the physiological adaptations made by the two breeds in response to work were similar.

Intensity of multigenerational carcinogenesis from diethylstilbestrol in mice.

Mice exposed prenatally to diethylstilbestrol (DES-exposed mice) can transmit a carcinogenic influence to the next generation (DES-lineage mice) when mated to control mice. The persistence of this effect was studied one generation further (DES-lineage-2 mice) by mating DES-lineage female mice to control males. The interaction of maternal dietary fat levels with DES was also tested by feeding high and low levels of dietary fat during the pregnancies that produced the final two generations. DES-lineage-2 mice, exposed to low or high fat maternal diets, had significantly more tumors than control mice with corresponding dietary fat exposure. The frequency of tumors in DES-lineage-2 mice was not significantly lower than in DES-lineage mice from a previous experiment. Thus, the multigenerational effect of DES is relatively intense in mice. If this type of carcinogenesis can occur in the human population, it poses a major threat to future generations.

Adding bentonite to sorghum grain-based supplements has no effect on cow milk production

Summary. Twenty-four Holstein–Friesian cows were used in an experiment comparing milk production from cows offered rolled sorghum grain either alone at 8 or 10 kg/head. day of air-dried grain or with 4% sodium bentonite. The design was a 4 × 4 latin square with a 1 week adjustment period and a 3 week treatment period. This design was used to highlight the effects of high levels of grain feeding and changing that level of grain or grain–bentonite every 4 weeks. Cows grazed either ryegrass (Lolium multiflorum cv. Tetila) or oats (Avena sativa cv. Cluan) during the day and a mixed ration based on maize silage, lucerne hay, and meat and bone meal at night. There was no significant effect of treatments on milk yield or composition. Cows fed bentonite had a higher (P&lt;0.05) rumen pH, tended to eat less grain sorghum and have lower concentrations of rumen ammonia and faecal starch. Faecal crude protein tended to increase with the use of bentonite indicating cows may have substituted pasture or mixed ration for grain and maintained a more stable rumen fermentation.