Impact of dietary cation anion difference in fish and pigs: a comparative study

Dietary cation anion difference (CAD, Na + K - Cl, mEq kg -1 ) determines the pH and acid base status of a diet, consequently affecting the acid base balance in the body compartments of animals. After feeding, a low dietary CAD will contribute more acids to the animals than a high dietary CAD. An optimal dietary CAD will increase the acid buffer capacity of a diet and this will help animals to compensate for metabolic acidosis. It is hypothesized that with an optimal dietary CAD, less energy will be needed for acid base regulation, indirectly improving feed intake and growth of animals. In the present study the effect of dietary CAD on growth performance, energy metabolism, acid base balance in the blood and in the digestive system were investigated in African catfish and pigs. The study consisted of 3 parts. Part 1 dealt with the growth response to dietary CAD and dietary Na/K ratio. Part 2 dealt with the energetic response to dietary CAD. Parts 3 dealt with the acid base balance in the blood and in the digestive system in response to dietary CAD. A negative dietary CAD (-100 mEq kg -1 ) resulted in a low feed intake and growth in both African catfish and young pigs. In African catfish, increasing dietary CAD from -100 to 700 mEq kg -1 led to a linear increase in growth.In pigs, the optimal dietary CAD was observed to be between 200 and 500 mEq kg -1 . The optimal dietary Na/K ratio in formulating dietary CAD was 1.5 to 2.5 (mol/mol) for African catfish. The lowest maintenance cost was observed at a dietary CAD level of 700 mEq kg -1 for African catfish. In pigs, dietary CAD of 200 mEq kg -1 tended to increase energy requirement for maintenance compared with dietary CAD of -100 mEq kg -1 , at restricted feeding. In pigs, a -100 mEq kg -1 CAD diet resulted in low blood pH, oxygen and HCO 3- content (mmol L -1 ) compared to a 200 mEq kg -1 CAD diet. During the postprandial period, however, pigs maintained a relative constant pH level in both portal and arterial blood within each CAD group. African catfish fed 700 mEq kg -1 CAD diet showed higher stomach digesta pH than fish fed -100 mEq kg -1 CAD diet both 0.5 and 3 h after feeding. However, no difference in pH of small intestine digesta was observed. In pigs, dietary CAD levels of -100 and 200 mEq kg -1 did not affect either stomach or small intestine digesta pH 2.5 h after feeding. The possible mechanisms of dietary CAD effect on feed intake and growth were discussed.</p

The impact of low concentrations of aflatoxin, deoxynivalenol or fumonisin in diets on growing pigs and poultry

In the present review, the quantitative impact of dietary aflatoxin, deoxynivalenol (DON) and fumonisin concentrations on performance of pigs and broilers is evaluated, with special emphasis on low concentrations of these toxins. Also, responses in performance of pigs and broilers to these three toxins are related to their absorption and elimination kinetics. By applying simple linear regression, information from many literature sources is integrated and condensed into, for example, estimates of depression in rates of weight gain, relative to non-contaminated diets, with increasing toxin concentrations. It was estimated that with each mg/kg increase of aflatoxin in the diet, the growth rate would be depressed by 16 % for pigs and 5 % for broilers. For DON, with each mg/kg increase in the diet, the growth depression was estimated at about 8 % for pigs, while broilers showed no response to DON concentrations below 16 mg/kg. Fumonisin showed the lowest impact on growth performance; with each mg/kg increase, the depression in growth rate was estimated at 0·4 and 0·0 % for pigs and broilers, respectively. Dietary concentrations that cause a 5 % reduction in growth rate were estimated at 0·3 and 1·0 mg/kg for aflatoxin for pigs and broilers, respectively; 1·8 and 0·6 mg/kg for pure and naturally contaminated DON for pigs, respectively; 21 and 251 mg/kg for fumonisin for pigs and broilers, respectively

Effect of phytase dose and reduction in dietary calcium on performance, nutrient digestibility, bone ash and mineralization in broilers fed corn-soybean meal-based diets with reduced nutrient density

The effect of reducing dietary Ca level (and Ca:P ratio) in combination with phytase supplementation, on broiler growth performance, nutrient digestibility, bone ash and mineralization, was investigated. A total of 2072 Ross 308 d-old male broilers were allotted to 7 dietary treatments with 37 birds/pen and 8 pens/treatment in a randomized block design. A positive control corn-soybean meal-based diet was formulated based on breeder's recommendations. Six test diets were evaluated in a 2 × 3 factorial arrangement including two levels of a Buttiauxella sp. phytase (500 and 1000 FTU/kg feed) and three Ca reduction levels (equivalent to 1.3, 1.6, 2.3 g/kg reduction and 1.6, 1.9 and 2.3 g/kg reduction in the 500 and 1000 FTU/kg phytase treatments respectively vs. PC). The reductions in available P (AvP) of the test diets were 1.46 and 1.74 g/kg in the 500 FTU/kg and 1000 FTU/kg phytase treatments respectively. Test diets were formulated by adding phytase, Ca and P supplements to a basal diet containing a reduction of 68 kcal ME/kg, on average 0.2 g/kg dig AA and 0.3 g/kg Na vs. PC. Diets were formulated in four phases. Excreta samples were collected on d 24 to 26 and 38 to 40 (from 5 birds transferred to cages on d 21 and 35 respectively) and ileal digesta and tibia samples were collected on d 10, 27 and 41. Compared to PC, feed conversion ratios (FCR) were reduced in growers fed medium or high Ca reduction and high phytase dose diets (P < 0.05). All phytase treatments improved energy efficiency (by up to 1.05 MJ/kg BWG) compared with the PC. Factorial analysis revealed a greater BWG and lower FCR with phytase supplemented at 1000 FTU/kg vs. 500 FTU/kg during starter and grower phases (P < 0.05). The high Ca reduction level (2.3 g/kg reduction vs. PC) reduced FCR in the finisher phase, and reduced overall (42 d) calorie consumption and feed cost per kilogram weight gain, compared with the low Ca reduction level (P < 0.05). Compared to the PC, phytase supplementation generally enhanced (by 10–30%) ileal, and total tract digestibility of P and, to a lesser extent Ca. Ileal digestibility of P at d 10 and d41 and Ca at d 41 were higher in the high- vs. the low-phytase groups. The high Ca reduction groups resulted in higher ileal P digestibility at d 10 and d41, ileal Ca digestibility at d27 and d41 vs. low Ca reduction groups (P < 0.05). Tibia ash was unaffected by dietary treatments, but bone Zn was increased at d 10 in all but one experimental diet vs. PC (P < 0.001) and was higher in the high- vs. the low-phytase groups (P < 0.01). Collectively, these findings indicate that a moderate (1.6 g/kg) to high (2.3 g/kg) reduction in dietary Ca in diets supplemented with 500–1000 FTU/kg of Buttiauxella phytase improved P and Ca digestibility, energy efficiency and productive performance in broilers fed corn-soybean meal-based diets

Soy Oligosaccharides and Soluble Non-starch Polysaccharides: A Review of Digestion, Nutritive and Anti-nutritive Effects in Pigs and Poultry

Soybean contains a high concentration of carbohydrates that consist mainly of non-starch polysaccharides (NSP) and oligosaccharides. The NSP can be divided into insoluble NSP (mainly cellulose) and soluble NSP (composed mainly of pectic polymers, which are partially soluble in water). Monogastric animals do not have the enzymes to hydrolyze these carbohydrates, and thus their digestion occurs by means of bacterial fermentation. The fermentation of soybean carbohydrates produces short chain fatty acids that can be used as an energy source by animals. The utilization efficiency of the carbohydrates is related to the chemical structure, the level of inclusion in the diet, species and age of the animal. In poultry, soluble NSP can increase digesta viscosity, reduce the digestibility of nutrients and depress growth performance. In growing pigs, these effects, in particular the effect on gut viscosity, are often not so obvious. However, in weaning piglets, it is reported that soy oligosaccharides and soluble NSP can cause detrimental effects on intestinal health. In monogastrics, consideration must be given to the anti-nutritive effect of the NSP on nutrient digestion and absorption on one hand, as well as the potential benefits or detriments of intestinal fermentation products to the host. This mirrors the needs for i) increasing efficiency of utilization of fibrous materials in monogastrics, and ii) the maintenance and improvement of animal health in antibiotic-free production systems, on the other hand. For example, ethanol/water extraction removes the low molecular weight carbohydrate fractions, such as the oligosaccharides and part of the soluble pectins, leaving behind the insoluble fraction of the NSP, which is devoid of anti-nutritive activities. The resultant product is a high quality soy protein concentrate. This paper presents the composition and chemical structures of carbohydrates present in soybeans and discusses their nutritive and anti-nutritive effects on digestion and absorption of nutrients in pigs and poultry

The Plackett-Burman design: An effective vehicle to evaluate multiple variables in poultry nutrition

Plackett-Burman (PB) designs are effective as they permit the assessment of 11 factors in a single experiment. The PB design ranks factors by their impact on response parameters, which is valuable for identifying factors to be optimized in subsequent studies. This design is novel to animal studies; therefore, the objective of this study was to evaluate the PB design in the context of phytase supplemented broiler diets. Eleven dietary factors were screened over 12 treatments at 2 levels (canola meal [0 or 125g/kg], wheat or maize [600 g/kg], whole barley [0 or 200 g/kg], digestible lysine [9.6 or 11.4 g/kg], phytate-P [2.6 or 3.3 g/ kg], Ca [6 or 10 g/kg], available P [3.0 or 4.5 g/kg], Na [1.6 or 2.0 g/ kg], xylanase level 1 [0 or 1200 U/kg], xylanase level 2 [0 or 2000 U/ kg], xylanase level 3 [0 or 2000 U/kg]; 3 xylanase factors were used to create a titration of xylanase activities derived from Trichoderma reesei of 0 to 5200 U/kg). Steam-pelleted diets based on wheat/maize and soybean meal with 1000 FTU/kg Buttiauxella phytase were offered to 468 male Ross 308 chicks (6 birds/cage, 6 replicates/treatment) from 7 to 28 d post-hatch. The effects of dietary treatments on weight gain, feed intake, gain:feed, relative gizzard weights, contents and pH were determined. Data were analyzed in JMP Pro 13 (SAS Institute Inc. JMP Software, Cary, NC) via PB screening methodology, with significant differences when P ≤ 0.05. Digestible lysine level was the most important positive factor influencing weight gain, feed intake and gain:feed (