Effect of consumption of potato chip scraps on the performance of pigs.

A two-phase study was conducted to determine the effect of potato chip scraps (PCS) consumption on dry matter intake (DMI), average daily gain (ADG), and gain: feed ratio (G:F) of nursery (Phase 1) and growing-finishing (Phase 2) pigs as well as carcass characteristics of the finished pigs. In Phase 1 (42 d), pigs (n = 138, avg BW 6.31 +/- .12 kg) were stratified by sex and weight and used in a randomized complete block design with three treatments in four blocks. Each treatment consisted of four pens of 11 or 12 pigs each. In Treatment 1 (control), pigs were fed a corn and soybean meal-based diet supplemented to meet NRC requirements. In Treatments 2 and 3, on an as-is basis, 15% and 20% of the corn, respectively, were replaced with 15% and 20% of PCS. Substitution of different levels of PCS for corn had no effect (P = .23) on the ADG of nursery pigs. However, DMI was reduced (P = .01) and G:F was improved (P = .004) linearly as the level of PCS in the diets was increased. In Phase 2, nursery pigs from Phase 1 were combined and continued on their respective treatments to study the effect of level of PCS consumption on the performance of growing and finishing pigs and carcass characteristics of finished pigs. In this phase, each treatment consisted of two pens of 22 to 24 pigs. Increasing the level of PCS resulted in a linear decrease (P = .07) in DMI and ADG (P = .001). However, G:F was linearly increased (P = .002) with increasing level of PCS in the diet. Increasing the level of PCS in the diets resulted in a linear decrease (P = .023) in the dressing percentage of the pigs. No other carcass characteristics or organoleptic effects were noted due to the PCS substitution in the diet of these pigs. This experiment demonstrates that PCS at the levels used in this study can be an effective substitute for corn in the diet of nursery and growing and finishing pigs.

Effects of feeding lasalocid and monensin on digestive tract flow and partial absorption of minerals in sheep.

Fifteen wethers (average BW 45.0 kg), fitted with abomasal and ileal cannulas, were fed a 70% concentrate diet alone or supplemented with 23 ppm of lasalocid or 23 ppm of monensin, DM basis. Wethers were fed 398 g of DM twice daily during a 10-d preliminary period, a 10-d total collection period, and a 6-d digesta collection period. During the total collection period, feed, feces, and urine were collected daily and composited. During the digesta collection, abomasal and ileal digesta and feces were collected at 12-h intervals, advancing 2 h each day, and composited. Feeding lasalocid and monensin increased (P < .01) urinary Mg excretion 17% and 19%, respectively. Lasalocid and monensin did not alter Ca and P metabolism. Feeding lasalocid decreased (P < .05) urinary excretion of Na 29%, whereas feeding monensin tended (P < .10) to increase it, compared with sheep fed the control diet. The effects of lasalocid and monensin were different for several variables compared with controls. Lasalocid and monensin altered absorption at different sites, overall absorption, and retention of minerals in sheep.

Effects of intravenous infusion of high levels of potassium and sodium on mineral metabolism in sheep.

A metabolism trial was conducted with 18 crossbred (Finn x Dorset x Suffolk) wethers, fitted with indwelling jugular catheters and abomasal and ileal cannulas, to determine the effects of high levels of i.v.-infused K and Na on mineral metabolism. The wethers (40 kg) were fed 800 g daily of a 60% concentrate diet in two equal portions at 0800 and 1900. Six wethers were infused randomly with 19 g K+, six with 10.6 g Na+ (chloride salts) and the other six with physiological saline solution (1.2 g Na) per day. Potassium chloride or NaCl infusion had no effects on apparent absorption, retention, flow or partial absorption of Mg, Ca and P in the digestive tract compared with physiological saline infusion. With all treatments, Mg and Ca were absorbed proximal to the abomasal cannula. Magnesium was secreted into, whereas Ca and P were absorbed from, the small intestine. Phosphorus was secreted both in the stomach and large intestinal regions of the digestive tract. Major sites of K and Na absorption were the small and large intestines, respectively. Infusion of K increased (P less than .05) retention of K compared with Na infusion. Infusion of Na increased (P less than .05) excretion and retention of Na compared with K infusion. Serum minerals were not changed by K or Na infusion compared with saline. The results of this experiment indicate that the depressing effects of K on Mg absorption are not attributable to high levels of absorbed K, but rather to K present in the digestive tract prior to the small intestine.

Influence of aluminum citrate and citric acid on mineral metabolism in wether sheep.

A 60-d trial was conducted to determine effects of Al citrate and citric acid on DM digestibility (DMD) and metabolism of Mg, Ca, P, K, Na and Al. Eighteen crossbred, yearling wether lambs equipped with ruminal cannulas were fed a basal diet containing .12% Mg and 2.87% K (DM basis) and were allotted to three treatments: 1) control, 2) 2,000 ppm Al as Al citrate and 3) citric acid equivalent to the citrate in treatment 2. Treatments were administered in 200 ml of deionized water twice daily in divided doses via ruminal cannula. Balance trials were conducted during d 0 to 5, 6 to 10, 25 to 35 and 50 to 60. Dry matter digestibility decreased (P less than .05) approximately 3 percentage units in lambs receiving Al. Treatment with Al citrate increased (P less than .01) apparent absorption and retention of Al compared to those receiving citric acid alone. Approximately 30% of ingested and infused Al was apparently absorbed. Compared to citric acid, Al citrate treatment lowered apparent absorption and retention of Mg and Ca during d 0 to 5. Apparent Ca absorption and retention again were lowered during d 50 to 60. Urinary Ca was increased (P less than .01) and apparent P absorption (P less than .10) and retention (P less than .05) were decreased by Al citrate during all measurement periods. Apparent absorption of K decreased (P less than .05) slightly in response to Al treatment. Apparent absorption of Na was not influenced by Al treatment. Serum Mg and P decreased and serum Ca increased in response to Al treatment. Results demonstrate negative effects of ingested Al, but not of citric acid, on DMD and metabolism of Mg, Ca, P and K.

Effect of ruminal infusion of glucose, volatile fatty acids and hydrochloric acid on mineral metabolism in sheep.

Two experiments were conducted to study the effects of alterations in ruminal pH and volatile fatty acid (VFA) concentrations on utilization of Mg and other minerals. In Exp. 1, two metabolism trials were conducted with 12 ruminally cannulated crossbred wethers fed 800 g/d of orchard-grass (Dactylis glomerata, L.) hay. After each feeding, wethers were ruminally infused with 500 ml (4.2 ml/min) or either 1) deionized water, 2) 40% (w/v) glucose solution, 3) .26 M propionic and .17 M butyric acid solution or 4) .35 M HCl. The pH of the VFA solution was adjusted to 6.8 with 10N NaOH. In Exp. 2, a metabolism trial was conducted with 12 ruminally cannulated crossbred wethers fed 600 g of orchard-grass hay and infused with a buffered VFA solution prepared as in Exp. 1 or with an unbuffered solution. In both experiments each trial consisted of a 5-d adaption period followed by four 5-d collections of feed, feces and urine. Compared with the glucose treatment, infusion of the buffered VFA solution produced similar acetic and propionic and higher (P less than .05) butyric acid concentrations (Exp. 1). The HCl solution produced changes in ruminal and pH values similar to those of the glucose infusion. In Exp. 1, apparent absorption of Mg was increased over twofold by the glucose infusion (P less than .05), but the other infusions had no effect. Apparent absorption of P was decreased (P less than .05) by HCl infusion, and K absorption was decreased by HCl and glucose infusions. In Exp. 2, infusion of the unbuffered VFA solution decreased apparent Mg absorption by 15.7%, compared with infusion of the buffered solution. These experiments suggest that the increased Mg absorption observed with carbohydrate supplementation is not due to alterations in ruminal pH or VFA levels.

Effect of supplemented magnesium from magnesium oxide or dolomitic limestone upon digestion and absorption of minerals in sheep.

Three metabolism trials were conducted with six lambs fitted with abomasal and ileal cannulae to determine the site of supplemental Mg absorption when supplied as dolomitic limestone or magnesium oxide. Magnesium intake was 1.09 g/d for the lambs fed the control diet and 2.21 and 2.10 g for those fed the dolomitic limestone and magnesium oxide supplemented diets, respectively. Irrespective of its source, the major site of Mg absorption was the preintestinal region. Magnesium was secreted in the small intestine in lambs fed all three diets. Magnesium supplementation resulted in an increase (P less than .05) in preintestinal Mg absorption, with magnesium oxide having the highest value. Supplementation had no effect (P greater than .05) on secretion or absorption of Mg from the small and large intestines or total retention of Mg. With all three diets, the major site of Ca absorption was the stomach region with additional absorption taking place in the large intestine. Calcium was secreted in the small intestine of lambs fed all treatments. Generally, K, Na and P were secreted in the preintestinal region and absorbed from the small and large intestines. The major site of K and P absorption appeared to be the small intestine and for Na, the large intestine. Serum minerals were unchanged (P greater than .05) due to treatment, but the levels of Mg, K and inorganic P tended to be higher in lambs supplemented with either of the Mg sources. It appears that the greater utilization of Mg from magnesium oxide vs dolomitic limestone is due to greater absorption of Mg from the forestomach region.