In contrast to corn, wheat and triticale exhibit high phytase activities. This enzyme enhances phytic phosphorus availability, as demonstrated in pigs given wheat diets. To study the utilization of triticale phosphorus in pigs, the importance of dietary phytase content and the mineral and bone disorders related to high phytate feeding, a nutritional experiment was carried out in 12 growing pigs fed either a corn- or a triticale-based diet for 6 wk. The diets were almost identical except for the cereal component; their phosphorus contents were low (0.4%) and mainly phytic. The following parameters were measured: calcium and phosphorus balances, bone and plasma contents of calcium and phosphorus, plasma vitamin D metabolites and parathyroid hormone (PTH), bone bending moments and intestinal phosphatase activities. Both diets provoked a phosphorus deficiency, but hypophosphatemia occurred less rapidly, hypercalciuria and hypophosphaturia were less marked and phosphorus availability was greater when the triticale diet was fed. This was attributed to the high phytase content of triticale because intestinal phytase and alkaline phosphatase activities were similar in pigs fed either diet. Calcium absorption was not modified by calcium retention was greater for pigs fed triticale and led to higher bone scores. In conclusion, the higher the phytase activity of the diet, the greater the phytate P availability and the lower the bone-mineral disorders.
P absorption and retention was two times higher in + D pigs than in -D animals (balance technique), and tibia X-ray pictures showed a lower bone density with the -D diet than with the + D diet. Surprisingly, vit. D supplementation had no effect on either of the mucosal enzymes (phytase and alkaline phosphatase). It may be concluded that vit. D improves phytate-P absorption via a mechanism which does not involve an increase in the activity of the intestinal phosphatases.Introduction.
containing 3.6 g lysine/1 000 kcal DE were compared. The control diet was based on wheat, soybean meal and mineral and vitamin mixture. Diets 2, 3 and 4 contained wheat (about 80 %), only 14.8 % soybean meal and were supplemented with 0.53 % lysine HCI, 0.07 % methionine and 0, 0.10 and 0.20 % threonine. The four diets contained 23.8, 18.3, 18.2, 17.7 In trial D, a control diet (T) containing 0.16 % methionine and 0.15 % cystine was compared to a diet TM (T + 0.08 % DL-methionine) and a diet TC (T + 0.08 % L-cystine). The trial was made in piglets weighing initially 10 kg fed ad libitum for 21 days. Methionine supplementation significantly improved performance. Cystine supplementation neither improved weight gain nor feed conversion ratio and decreased feed intake. It was concluded that methionine should represent at least 55 % of sulphur amino acid supply. Dietary calcium excess may decrease phytic P digestibility in hamsters and rats and bone breaking strength in pigs. An experiment was made to compare Ca and P balances, mineral content, density and bending moment of bones in pigs fed either a high (1.4 %) or a normal (0.6 %) Ca diet for 2 months. No inorganic P was added and the total P (0.5 %), of which 70 % was phytic, and vitamin D 3 (1 000 IU kg) contents were the same in both diets.
Both diets caused a phosphorus deficiency, but hypophosphatemia occurred more rapidly while hypercalciura and hypophosphaturia were more marked with maize than with triticale. P absorption and retention were higher with T diet than with M diet : apparent absorption, 65 + 1 vs 48 ± 3 p. 100 intake, respectively (P < 0.01). This was probably related to the high phytase activity of triticale since phosphatase activities (phytase and alkaline phosphatase) of intestinal mucosa were similar in both groups of animals. Calcium absorption was not modified by the kind of cereal given, whereas Ca retention was greater on triticale than on maize diet. The higher mineral retention observed in triticale fed pigs led to significantly higher bone mineral contents. In addition, average daily gain and feed efficiency were significantly better in the triticale fed group. In conclusion, the higher the dietary phytase activity, the higher the phytate phosphorus availability.
The high CA diet had no effect upon phosphorus utilization. Daily amounts of excreted, absorbed and retained calcium were increased whereas Ca absorption relative to intake was not significantly decreased in high CA fed pigs. All In various species, phosphorus deficiency, but also phosphorus excess may develop mineral and bone disorders. These disorders were studied in the growing pig by comparing the effects of three dietary phosphorus levels (from deficiency to excess) on some mineral metabolism parameters : urinary Ca and P excretions, plasma and bone mineral contents, bone bending moment and density. The low P diet (0.4 % P) was not supplemented with mineral P, the high P diet (1.2 % P) contained 0.4 % plant P and 0.8 % mineral P and the control diet (0.7 % P) around 60 % plant P and 40 % mineral P. Ca (0.8 %) and vitamin D 3 (500 IU/kg diet) contents were the same for all diets. Animals were killed after a 7-week period. P-deficient pigs exhibited hypophosphatemia, hypophosphaturia, higher plasma alkaline phosphatase, hypercalciuria as well as decreased mineral contents (about -20 %), density and bending moment of all bones. The high P-diet did not change any plasma parameters, but provoked a very acute hyperphosphaturia, a severe nephrocalcinosis. It also decreased the strength of some bones (tibia, metatarsal), but did not change their mineral contents or density. In conclusion, the disorders in mineral metabolism are more marked with low than with high P diets. However, high P-related disorders should be taken into account in practical husbandry when formulating diets.Utilization of tandem rapeseed by weaned piglets and growing-finishing pigs The feeding value of Tandem rapeseed (52 [tmoles glucosinolate/g defatted dry matter) was studied in diets for 10-25 kg weaned piglets and for 27-102 kg growing-finishing pigs. Barley based diets containing either 0-5 or 10 % raw rapeseed or 20 % extruded rapeseed were compared. These diets were formulated to supply 3.6 g lysine/1 000 kcal DE to piglets and 2.6 g to growingfinishing pigs. They were fed ad libitum to piglets and according to a feeding pattern to pigs.In the piglet trial, energy intake was reduced by 3.4 and 4.1 % with diets containing 5 and 10 % raw rapeseed. With extruded rapeseed, energy intake was reduced by 5 %. Feed conversion ratio was similar whatever the diet. Consequently, growth of piglets mainly depended on the level of energy intake.
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