Does the pelleting process affect the nutritive value of a pre-starter diet for suckling piglets? Ex vivo studies on mineral absorption

Digestibility of calcium in feed ingredients and requirements of digestible calcium for growing pigs

Efforts to reduce phosphorus (P) excretion from pigs have increased during the past few decades and it has been recognised that interactions among dietary P, calcium (Ca), phytate, and microbial phytase exist. However, limited research has been reported on Ca digestibility, but to optimise the use of both Ca and P, digestibility values of Ca are needed. Due to endogenous losses of Ca, values for standardised total tract digestibility (STTD) of Ca in different Ca supplements and feed ingredients have been determined, and these values may be used to formulate mixed diets. Phytate may bind intrinsic Ca in feed ingredients of plant origin as well as extrinsic Ca from ingredients of animal origin or Ca supplements, but not all forms of Ca in Ca supplements will bind to phytate. Therefore, the effect of phytase on the STTD of Ca may vary depending on the amount of Ca bound to phytate and in some cases microbial phytase will result in increased STTD of Ca from animal proteins or Ca supplements. Dietary fibre may increase the STTD of Ca, but particle size and soybean oil do not influence the STTD of Ca. Requirements for digestible Ca by growing pigs has not yet been determined, but with the availability of values for the STTD of Ca in most commonly used feed ingredients, the basis for determining such values has been prepared. In conclusion, data for the STTD of Ca and the effects of microbial phytase in many feed ingredients have been determined and future research will be directed at determining the requirements for digestible Ca by different groups of pigs.

Quantitation of Maillard reaction products in commercially available pet foods

During processing of pet food, the Maillard reaction occurs, which reduces the bioavailability of essential amino acids such as lysine and results in the formation of advanced Maillard reaction products (MRPs). The aim of this study was to quantitate MRPs (fructoselysine (FL), carboxymethyllysine (CML), hydroxymethylfurfural (HMF)) and the cross-link lysinoalanine (LAL) in commercial pet foods. Sixty-seven extruded, canned, and pelleted dog and cat foods for growth and maintenance were analyzed using UPLC-MS. Canned pet foods contained on average the most FL, CML, and HMF (4534, 37, and 1417 mg/kg dry matter, respectively) followed by pelleted and extruded foods. Average daily intake (mg/kg body weight(0.75)) of HMF is 122 times higher for dogs and 38 times higher for cats than average intake for adult humans. As commercial pet foods are most often the only source of food for dogs and cats, future research focus should be on the bioavailability and long-term health implications of MRP consumption by dogs and cats.

The Maillard reaction and pet food processing: effects on nutritive value and pet health

The Maillard reaction, which can occur during heat processing of pet foods or ingredients, is known to reduce the bioavailability of essential amino acids such as lysine due to the formation of early and advanced Maillard reaction products (MRP) that are unavailable for utilisation by the body. Determination of the difference between total and reactive lysine by chemical methods provides an indication of the amount of early MRP present in foods, feeds and ingredients. Previous research reported that the difference between total and reactive lysine in pet foods can be up to 61.8%, and foods for growing dogs may be at risk of supplying less lysine than the animal may require. The endogenous analogues of advanced MRP, advanced glycation endproducts, have been associated with age-related diseases in humans, such as diabetes and impaired renal function. It is unknown to what extent advanced MRP are present in pet foods, and if dietary MRP can be associated with the development of diseases such as diabetes and impaired renal function in pet animals. Avoidance of ingredients with high levels of MRP and processing conditions known to favour the Maillard reaction may be useful strategies to prevent the formation of MRP in manufactured pet food. Future work should further focus on understanding the effects of ingredient choice and processing conditions on the formation of early and advanced MRP, and possible effects on animal health.

Effect of feed processing and enzyme supplementation on diet digestibility and performance of male weaner pigs fed wheat-based diets in dry or liquid form

One hundred and forty-four individually housed, entire male (Large White × Landrace) weaner pigs (28 days; 7.3 s.d. 0.1 kg) were individually housed and allocated to a 26-day feeding trial of 2 by 2 by 3 factorial design. The factors were (1) feed processing method (meal or steam pelleted), (2) feed form (dry or liquid), and (3) enzyme addition (basal diet, or basal diet plus 300 ppm xylanase or 100 ppm phytase). Five days post weaning, two pigs were removed from each treatment. The basal diet was formulated to be marginally adequate for pigs of this age, providing 13.8 MJ digestible energy (DE)/kg DM and 0.79 g available lysine/MJ DE. The diet contained 0.81% Ca, 0.44% non-phytate-P and 0.31% phytate-P. Compared with pigs fed dry diets, pigs fed liquid diets consumed less feed (70 ± 14.2 g/day; P < 0.05) had a lower daily gain (49 ± 12.5 g/day; P < 0.05) and as a consequence had a lower 26-day weight (1.1 ± 0.4 kg; P < 0.05). However, pigs fed liquid diets had a better feed conversion efficiency (adjusted to the same DM content as dry feed) than pigs on dry diets (1.16 versus 1.20 ± 0.02; P < 0.05). Steam pelleting the diets had no effect on feed intake or daily gain, but did improve feed conversion ratio (1.14 versus 1.22 ± 0.02; P < 0.05). The poorer growth on liquid feeds appeared to result from the feeding method imposing a degree of restriction on feed intake. Xylanase or phytase supplementation did not significantly affect non-starch polysaccharide levels in the diets or growth performance. Phytase supplementation increased (P < 0.05) daily intake, daily gain and 26-day weight, of pigs fed dry diets, but not those fed liquid diets. The results indicated that when diets were fed in liquid form, prior steam pelleting of the diets and enzyme supplementation did not provide additional benefit.