Riboflavin requirement of lactating swine

Twenty-five crossbred gilts and 25 crossbred sows were used in an experiment to estimate the riboflavin requirement of lactating swine. During gestation the females were fed a 12% crude protein, corn-soybean meal diet that was marginal in riboflavin content, i.e., 2.3 mg/kg. After farrowing, litter size was equalized across lactation diets within each parity category. The basal, 14% crude-protein corn-soybean meal lactation diet was supplemented to provide five levels of dietary riboflavin: 1.25, 2.25, 3.25, 4.25 and 5.25 mg/kg. Five gilts and five sows were fed each dietary treatment. Each dam was provided her assigned diet ad libitum during the 24-d lactation; piglets were not provided supplemental feed. The erythrocyte glutathione reductase activity coefficient (EGRAC), an indicator of riboflavin status, was measured on blood samples obtained from the dams and their piglets on d 1 and d 24 postpartum. On d 1, the mean EGRAC of gilts was slightly higher than that of sows, while piglet EGRAC was similar regardless of maternal age. On d 24 gilts and their piglets had higher average EGRAC (P less than .01) than did sows and their piglets. Thus, there was a treatment x dam age interaction (P less than .05). Lactation performance criteria gave further evidence of similar treatment x age group interactions. Gilts fed the diet containing 1.25 ppm riboflavin had higher piglet mortality, consumed less feed and lost more weight (P less than .05) for each criterion than did sows fed the same diet. Despite these observations, the broken-line estimates of the riboflavin requirement, based on EGRAC, for gilts and sows were 16.3 and 16.2 mg/d, respectively. The EGRAC values for piglets closely paralleled those of their dams regardless of treatment, suggesting that there is no mechanism to protect the nursing piglets from a maternal dietary deficiency of riboflavin.     

Choline requirement of the laying hen. 2. Effect of methionine and fat content of rations on choline requirement

165 laying hens per group received 3.0, 3.5, or 4.0 g methionine, 29 or 59 g fat and supplements of 0, 108, 217, 434 or 868 mg choline per kg feed resp. (3 X 2 X 5) over a period of 336 days. The average laying performance was 70% and was not influenced values by the content of the feed. The methionine supplements significantly increased the weight of the eggs by 0.6 and 1.1 g resp. The higher fat content increased the weight of the eggs by 0.6 g. Feed expenditure was not influenced by the subject of the experiment. The results of the experiment show that laying hens do not require choline as feed supplement and that therefore no interactions between choline and the fat and methionine content of the ration are to be expected.     

Vitamin E requirement of growing swine

The vitamin E requirement of growing pigs was estimated on the basis of prevention of morphological signs of deficiency. Five groups of pigs were fed a barley-based diet low in vitamin E that contained 16 mg of DL-alpha-tocopheryl acetate equivalents/kg and .1 ppm of Se for 4 wk (depletion I). This period was followed by 7 wk of supplementation, during which the groups received 0, 15, 45, 135 and 405 mg of supplemental DL-alpha-tocopheryl acetate/kg diet. Finally, all the animals were fed the low vitamin E diet for 7 wk (depletion II). To follow the vitamin E concentration in serum and tissues, blood samples were collected and biopsies were taken from skeletal muscle, adipose tissue and the liver throughout the experiment. The peak vitamin E value was observed in the liver, followed by the adipose tissue and then skeletal muscle. The liver responded rapidly to changes in dietary vitamin E intake, whereas the adipose tissue and the skeletal muscle reacted at a slower rate. In spite of the abundant occurrence of the different vitamin E isomers in the feed, alpha-tocopherol was the main isomer detected both in the serum and in the tissues. The activity of glutathione peroxidase in serum increased with age but was independent of the serum vitamin E concentration. In the unsupplemented group all animals suffered from the vitamin E and Se deficiency syndrome (VESD) in an acute or chronic form. A total of 31 mg of DL-alpha-tocopheryl acetate/kg diet (16 mg of naturally occurring vitamin E and 15 mg as supplementation) equivalent to 2.5 IU vitamin E/g polyunsaturated fatty acids (PUFA) was enough to prevent the development of VESD. In view of the large individual variations of vitamin E concentration in target organs, and to obtain a certain safety margin for prevention of VESD in growing pigs, a supplement of 30 mg of DL-alpha-tocopheryl acetate/kg diet is recommended.     

Threonine requirement for reproduction in swine

An experiment was conducted to estimate the threonine requirement of pregnant swine. L-threonine was added to a fortified corn-gelatin diet and fed at a rate to provide five threonine levels of 3.59, 4.95, 6.31, 7.67 and 9.03 g/d. Twenty-five crossbred gilts were randomly assigned to these five dietary treatments. Increasing threonine resulted in a difference (P less than .01) in nitrogen (N) retention, with maximum retention at 4.95 g/d threonine intake. Blood samples were drawn before and after feeding. Although plasma urea N did not change significantly, the lowest level occurred at an intake of 4.95 g/d threonine. As threonine intake increased, plasma threonine increased quadratically (P less than .05). This increase was accompanied by a quadratic (P less than .005) decrease in plasma lysine. Sow weight gains increased quadratically (P less than .01) with increasing threonine levels. Litter weight, number of pigs born, baby pig gains, daily milk yield and milk protein were not influenced by threonine levels. The lysine-alpha-ketoglutarate reductase activity of the sow liver samples increased linearly (P less than .05) as dietary threonine levels increased. Based upon metabolic criteria 4.95 g/d L-threonine met the requirement for animals in this experiment. If 75% of threonine in a corn-soybean meal diet is available, the threonine requirement for reproduction would be no higher than 5.4 g/d or .30% dietary threonine when daily feed intake is 1.82 kg.     

Experimental hexachlorophene intoxication in young swine.

Hexachlorophene (HCP) intoxication in swine was studied as a possible model of HCP poisoning in human beings. Swine were topically or orally given HCP each day, and observations were made on central nervous system function, hematologic measurements, serum chemical analyses, necropsy, microscopic examination of tissues, and concentrations of HCP residues in blood and tissue. Intoxication was observed in orally exposed swine, but the syndrome was not consistently produced in topically exposed swine. Signs and microscopic lesions were all related to dysfunction of the central nervous system, e.g., incoordination, paresis, and status spongiosus. Occurrence of signs and lesions, mortality rates, and concentrations of HCP residue were positively correlated with the dosage of HCP given.     

Vitamin A requirement of growing swine. 1. Effect of vitamin A supply on growth of piglets and fattening swine

For the purpose of ascertaining the vitamin A requirement seven experiments with 303 pigs in the live weight range between 6.5 and 114 kg were made. In three experiments under in practice conditions we checked the standard vitamin A supplement to the mixed feed with 1,732 pigs (live weight range between 8.5 and 110 kg). The supplement to vitamin-A-free rations and to those poor in or free of carotene amounted to between 0 and 8,000 IU/kg feed. Above that, between 0 and 16 mg beta-carotene and 1,000 mg nitrite/kg feed were supplemented. As long as the vitamin A store in the liver during weaning amounted to greater than 50 IU and greater than 100 IU/g at the beginning of fattening, feed intake, live weight growth and feed expenditure were not influenced by the supplement of vitamin and provitamin resp. The supplement of 250 IU resulted in the same weight growth from weaning to the end of fattening as that of 4,000 IU. Nitrite supplement had a negative effect at 250 IU, at 500 IU vitamin A consumption and weight growth tended to be only insignificantly lower. The methaemoglobin content decreasing in the course of the experiment reflects the adaptation of the pigs to the nitrite load. The consumption and growth depression caused by vitamin A deficiency could be observed from the 7th week of the experiment when casein-swelling starch rations were fed, but from the 13th week of the experiment only when cereal-soybean oilmeal rations were fed. The weight of liver, spleen, kidneys, heart and brain was not influenced by vitamin A supply. The same applies to the body composition and retention with the exception of two deficiency piglets, which contained less fat in the empty body than the control animals.     

Histidine requirement of the young pig

A histidine (HIS)-deficient, feather meal-corn-dried whey basal diet (19% protein and 3,200 Kcal ME/kg), supplemented with lysine, methionine and tryptophan, was employed to determine the HIS requirement of the growing pig between 10 and 20 kg live weight. Using a chick bioavailability growth assay, the HIS-deficient basal diet was found to contain .19% bioavailable HIS. A preliminary pig study established that the HIS-deficient basal diet was capable of supporting good growth of pigs when supplemented with sufficient L-HIS.HCl.H2O. In the second pig experiment, crossbred pigs with an average initial weight of 10 kg were kept in individual metabolism crates and were fed to appetite in two feedings the HIS-deficient basal diet supplemented with 0, .06, .12 or .18% L-HIS. Rate and efficiency of weight gain increased linearly between 0 and .12% supplemental HIS, but the highest supplemental level of HIS did not improve performance further. Plasma HIS increased, whereas plasma urea-N remained unchanged, as the level of dietary HIS increased. The third pig experiment employed narrower increments of .06, .09 or .12% supplemental HIS, and a linear response in both gain and feed efficiency occurred. Viewing all experiments together, the bioavailable HIS requirement of the 10- to 20-kg pig was .31% of the diet. Assuming an 85% bioavailability of HIS in commercial diets based on corn and soybean meal, the total HIS level needed in practice would be .36%.     

Energy requirement of young female cattle. 3. Reproduction and products of conception

The results with regard to reproduction obtained from a study lasting several years of the energy requirement of young female cattle reared with different intensity are described. It becomes apparent that there are relations between feeding, rearing intensity and insemination expenditure. Age and weight at the time of conception in the individual test series averaged between 290 and 630 days and 270 and 430 kg respectively. The weight of the conceptional products of 31 calvings was registered and, according to Jakobsen (1956, 1957), the energy and N content of the conceptional products was proportionally assigned to the prenatal test periods. In the last 140 days of gravidity the N balance per animal and day increases from 16 to 23 g. N retention of the cows is low in the last days of gravidity. The utilization of metabolizable energy for the development of conceptional products is calculated as a conventional comparative value provided the maintenance requirement per unit metabolic body weight of the cows and the utilization of metabolizable energy for energy retention in the cows on an average of 156 individual values of 12 +/- 8% are the same and correspond in their magnitude to analogous findings of other authors, mainly compiled from dairy cows.     

The energy requirement of young female cattle. 2. Substance and energy metabolism

The second installment of information on studies over several years of the energy requirement of young female cattle comprises data of the feed intake, the digestibility and metabolizability of the rations used as well as the nitrogen and energy balances of the test animals in six experiments with varying rearing intensities, in which the N, C and energy balances as well as rumen physiologic values were measured monthly using the respiration test technique. Of four experiments, measured values are available over the whole rearing period from calf to calving. The results received from 680 interpretable test periods are-separated for the six experiments--arranged in aggregate form according to live weight range in order to characterize the development of nutrient and energy metabolization processes at various rearing intensities. The results form an essential basis for the derivation of the energy requirement of young female cattle according to factorial criteria.     

Energy value of cassava for young swine

A comparative slaughter experiment was conducted to determine the energy values of cassava chips for weanling pigs. A basal, highly fortified diet was fed to all pigs at 3% body weight daily. Treatments consisted of the addition of cassava chips at 0, 1, and 2% of body weight daily. The apparent digestion coefficients (ADC) for dry matter and energy increased but the ADC for nitrogen decreased with the addition of cassava chips to the basal diet. Digestible energy per gram decreased linearly and quadratically (P less than .01), but metabolizable energy and net energy per gram remained constant with the addition of cassava chips. Metabolizable energy as a percentage of digestible energy increased linearly and quadratically (P less than .01) with the addition of cassava chips to the basal diet. Daily gain of nitrogen, ether extract, and energy increased linearly (P less than .01) as cassava chips were added to the basal diet, but daily gain of ash remained relatively constant. Pooled energy values determined for cassava chips in kcal/g of dry matter were: gross energy, 4.04; digestible energy, 3.58; metabolizable energy, 3.48; nitrogen-corrected metabolizable energy, 3.22; and net energy, 2.57. Net energy of cassava chips for weanling pigs is close to that of corn.     

Vitamin E requirement of chicks and young hens

In 4 experiments young chickens of the species White Leghorn received semisynthetic rations with a vitamin E content less than 1 mg/kg basal ration. Sunflower oil heated with FeCl3 supplement was used as a factor increasing requirement. Feed intake, live weight gain and feed expenditure with semisynthetic rations without oil supplements did not depend on vitamin E supplements. After the feeding of rations without vitamin E animal losses were higher. The losses were normalized by 1 mg vitamin E supplement per kg feed. Rations containing sunflower oil without vitamin E supplementation resulted in encephalomalacia of the young chickens. Vitamin deficiency increased triiodine thyronine content in the blood plasma. Antibody formation after the application of human gamma globulin did not depend on the vitamin E supply studied. A vitamin E requirement of young chickens and young hens of the laying species of less than 1 mg/kg mixed feed is derived from the results.     

The energy metabolism of growing swine in a live weight range of 10-50 kg. 3. Energy maintenance requirement of growing swine]

Investigations into the energy maintenance requirement yielded the following results: For the energy maintenance requirement (EMR) in dependence on live weight (LW) using the relation EMR = aLWb from 13 experiments, an exponent of the live weight of 0.647 +/- 0.054 (0.57 to 0.73) was found out. Increasing the protein content in the feed from approximately 17 to approximately 45% in 6 experiments lowered the energy maintenance requirements about 14, 4, 6, 2, 6 and 12% respectively. The animals' development had no influence on the difference. The amount of the energy maintenance requirement varied greatly between the experiments. Exclusively in the experiments with barrows, a lowest value of 634 and a highest value of 931 kJ metabolizable energy per kg LW0.62.d was measured. On average of 19 comparisons the energy maintenance requirement derived from growth and maintenance periods by means of regression analysis was significant (alpha = 0.05), about 4% higher than the energy maintenance requirement measured on maintenance level directly.