L.A. den Hartog

The effect of including various structural polysaccharides in pig diets on ileal and faecal digestibility of amino acids and minerals

Abstract Ten pigs with average initial weight of 40 kg fitted with ileo-caecal re-entrant cannulae were used in order to determine the effect of inclusion of different structural polysaccharides in the diet on ileal and faecal digestibilities of amino acids and minerals. The experiment comprised 4 treatments: (I) 100% control diet; (II) 95% control diet+5% pectin; (III) 95% control diet+5% cellulose; (IV) 95% control diet+5% ground straw. The ileal digestibility of organic matter was reduced by cellulose inclusion. The same effect occurred for the faecal digestibility of organic matter after cellulose and straw-meal inclusion. The ileal digestibility of protein was reduced after inclusion of straw-meal in the diet. The following amino acids showed a reduced ileal digestibility after 5% straw-meal inclusion in the diet: isoleucine; lysine; phenylalanine; threonine; valine; alanine; aspartic acid; glutamic acid; tyrosine. The faecal digestibility of protein did not differ among diets. With the exception of the apparent faecal digestibility of calcium, none of the determined ileal and faecal mineral digestibilities were significantly lower, as an average, in pigs fed the diets in which the structural polysaccharides were included. When pectin was included, the ileal digestibilities of Na, K, Mg, Ca and P were slightly depressed, while over the whole digestive tract there was no effect. The amount of Na that passed the distal ileum was 4.6 to 5.2 times higher than the Na intake.

Studies on the threonine requirements of growing pigs based on the total, ileal and faecal digestible contents

Abstract The threonine requirement of pigs based on total threonine or on ileal and faecal digestibilities, was investigated. Studies were carried out in nine pigs fitted with ileo-caecal re-entrant cannulas and 10 non-cannulated pigs to determine the ileal and faecal digestibilities of amino acids in two diets. Diet 1 consisted of corn (75.8%) and soybean meal (20.9%); Diet 2 consisted of corn (48.5%), hominy feed (40.0%) and meat meal (10.7%). Diet 2 caused a large difference between the ileal and faecal digestibility of threonine, 56.9 vs. 79.1%, respectively. The difference in ileal digestibility of threonine between the two diets was 16.4 percentage units, while the difference in faecal digestibility was 5.1. In Diet 1, the ileal and faecal digestibility for threonine was 73.3 and 84.2%, respectively. A growth trial using 120 pigs was carried out over the liveweight range of 17–50 kg. Based on the results of the digestibility studies, five isocaloric and isonitrogenous diets were formulated. Diet 2 was supplemented with amino acids, with the exception of threonine, up to the ileal supply of the amino acids in Diet 1 in the digestibility trial. Thereafter, Diet 2 was divided into five equal portions to which stepwise additions of 0.05% threonine were added. Feed intake was reduced in the threonine-deficient diets. Because of the low ileal digestibility of threonine in Diet 2, the total requirement was relatively high. The average daily gain of the piglets did not increase when the threonine content of the diet was > 0.70%. Based on the supply of threonine, as measured by the ileal analysis method, this content was 0.44%. Based on the faecal analysis method, this content was 0.57%. The present studies demonstrated that the difference between the faecal and ileal digestibility of threonine is not constant between diets. This indicates that the requirement for threonine should be related to ileal digestibility and not to faecal digestibility.

Vitamin E and its role in the nutrition of the gilt and sow: A review

Abstract There is evidence that supplementation of most sow diets with vitamin E is necessary. The common recommendation for supplemental vitamin E in sow diets is 10–20 IU kg −1 diet. This level of vitamin E is adequate to meet needs of the sow for reproduction and to maintain body reserves of α-tocopherol over several parities. Reproducing females can tolerate lower dietary intakes of vitamin E if the levels of Se in the diet are adequate. If body reserves are maintained, the sow, through the colostrum and milk, can supply the neonate with the α-tocopherol required for normal growth and maintenance of tissue integrity. The neonatal piglet is dependent on the sows colostrum for its α-tocopherol requirements as little placental transfer of vitamin E occurs during gestation. Placental transfer of α-tocopherol is resistant to dietary manipulation while colostral transfer can be enhanced by dietary supplementation. The dietary level of vitamin E in the sow gestation and lactation diet optimal for immune function in both sow and her piglet has not been established. Based on preliminary studies, the level needed is higher than that stated above for growth and reproduction. Enhancements in immune response have been observed with additions of 40–60 IU vitamin E kg −1 diet. This potential for enhancement of the sows and piglets immune response by dietary supplementation of vitamin E represents a possibility to improve pre-weaning survival of piglets.

Between- and within-herd variation in the digestibility of feed for growing-finishing pigs

Abstract The variation in digestibility between and within pig herds was studied on 17 farms. Digestibility coefficients, using HCl-insoluble ash as a marker, were determined at two different stages of the growing period (35–40 and 65–70 kg). At each experimental stage, a single feed from the same batch was given. Digestibility of organic matter varied between farms from 77 to 84% for pigs of 35–40 kg liveweight and from 78 to 86% for pigs of 65–70 kg liveweight. The variation in digestibility between farms was considerably higher than that within farms for pigs of 35–40 kg liveweight. There was a significant relationship between digestibility and dry matter content of the faeces: a one unit increase in the dry matter content of the faeces was accompanied by a one unit increase in the digestibility of the organic matter.

The effect of dietary electrolyte balance on blood parameters and the performance of veal calves

Ninety-six Dutch red and white male veal calves were used in a 19-week feeding trial with 5 diets differing in dietary electrolyte balance (dEB = Na + K - Cl). These dEBs were 6.4, 15.7, 25.0, 34.4 and 43.8 meq 100 g−1 of feed for Diets 1, 2, 3, 4 and 5, respectively. These balances were achieved by adding NH4Cl (1.0 or 0.5%) or sodium citrate dihydrate (2.51 or 1.75%) to a milk replacer. With Diets 2, 3 and 4 the growth rate and the feed conversion ratio were not significantly different (P > 0.05). Compared to the mean results obtained with the 3 other diets, the low-dEB (1) and the high-dEB (5) diets caused a mean reduction of 8% in live weight gain and a mean increase of 5% in feed conversion ratio. n nThere were no significant differences (P > 0.05) among treatments in carcass classification characteristics. The pH, bicarbonate level, pCO2 and base excess of the blood were significantly decreased, while the blood chloride level was increased (P 0.05) in the blood parameters between animals fed Diets 2, 3, 4 or 5.

The effect of environmental temperature on metabolic rate and partitioning of energy intake in breeding boars

Abstract An experiment was performed to study the effect of ambient temperature on metabolic rate and partitioning of energy intake in breeding boars. In each of two trials, four Yorkshire boars (10–13 months old, 224 kg liveweight) were housed in balance cages in an open-circuit calorimeter. Each boar was fed 480 kJ of metabolizable energy (ME) per kg liveweight (W 0.75 ) day −1 . Semen was collected twice weekly. In both trials temperature was decreased subsequently from 24 to 20, 16, 12 and 10°C (3.5 days per temperature treatment). After 7 days at 10°C temperature was increased in reversed order to 12, 16, 20 and 24°C (3.5 days each). Measurements of metabolic rate were carried out every 3.5 days and collection of excreta occurred weekly. The estimated lower critical temperature, extra thermoregulatory heat production and maintenance heat production were 20°C, 16 kJ kg −1 W 0.75 day −1 °C −1 , and 382 kJ kg −1 W 0.75 day −1 , respectively. The results from both trials were in close agreement. Digestibility of energy, protein and dry matter and metabolizability of energy intake were not influenced by ambient temperature. Above the critical temperature, energy balance, protein and fat retention were 70 kJ kg −1 W 0.75 day −1 , 103 g animal −1 day −1 and 41 g animal −1 day −1 , respectively. Below the lower critical temperature, protein and fat gain decreased about 10 and 20 g animal −1 day −1 °C −1 . At 10°C the boars lost 156 g fat day −1 , while above 20°C they gained 41 g fat day −1 on the same feeding level.