Novel edible toys as iron carrier to prevent iron deficiency of postweaned pigs.

The current preventive treatment for iron deficiency in pigs is inefficient, resulting in a high prevalence of iron-deficient or anemic postweaned pigs. The aim of this study was to develop and characterize edible toys (ETs) to be used as oral iron supplements, and to assess their effect on feeding behavior and iron status of postweaned pigs. Three types of ETs, varying in sweetness, were produced by ionic gelation, using whey, sodium alginate, ferrous sulfate and atomized bovine erythrocytes. ET control (ETC) was developed without sweetener, ET1 contained 15% w/v sucrose and ET2 contained 0.03% w/v of Sucram (98% sodium saccharin, 1% neosperidine dihydrocalcone and 1% maltol). ETs were mainly composed of carbohydrates and protein, with a similar concentration of iron (2.2-2.7 mg/g). The ETs were offered to 24 postweaned pigs to measure acceptability and preference. The animals preferred ETC and ET2 over ET1. To assess the nutritional benefit of the ETs, 24 postweaned pigs were distributed into three groups: ETC (without iron), ETC-Fe (ETC with iron) and ET2-Fe (with iron and Sucram). Iron-loaded ET (ETC-Fe and ET2-Fe) significantly increased the concentration of red blood cells (from 6.1 to 7.5·106 x mm3 for ETC-Fe and from 6.2 to 7.8 for ET2-Fe), hematocrit (from 32.8 to 37.9% for ETC-Fe and from 32.3 to 35.1 for ET2-Fe), serum iron (from 28.6 to 120.6 µmol/L for ETC-Fe and from 34.9 to 145.4 for ET2-Fe) and serum ferritin (from 7.8 to 18.5 µg/L for ETC-Fe and from 8.1 to 20.2 for ET2-Fe). In conclusion, the ETs developed in this study were accepted by the pigs and provided adequate iron to improve the iron status of postweaned pigs.

Acquisition of flavour preferences in pigs through interactions with conspecifics that had previously consumed flavoured protein solutions.

It is known that pigs can acquire flavour preferences by brief social interactions with conspecifics that previously consumed a flavoured solid feed. However, there is no information about whether a flavoured solution could support flavour preferences through social transmission. Ninety-six pigs (49 days old) were housed in 12 pens (8 pigs/pen). Four animals per pen were randomly selected to act as observers and four as demonstrators. Demonstrator animals were temporarily moved to an empty pen where a protein solution was offered (porcine digestive peptides (PDPs), 4% weight/volume) with the addition of 0.075% aniseed (six pens) or garlic (six pens) powdered artificial flavours for 30 min. Afterwards, demonstrators were returned to interact with observer animals for 30 min. A choice test (30 min) between aniseed and garlic PDP was performed for each observer group after the interaction. Observers showed a higher intake of solutions previously consumed by their demonstrator conspecifics (648 v. 468 ml; SEM 61.36, P < 0.05). As with flavoured solid feeds, protein solutions containing artificial flavours can create preferences in pigs for those flavours through social transmission from conspecifics.

The use of porcine digestible peptides and their continuity effect in nursery pigs.

A total of 552 entire male and female nursery pigs were selected to be used in 2 different experiments that aimed to study if milk ingredients can be replaced by highly preferred protein sources (Exp. 1) and if pre- and postnatal exposure of those protein ingredients through the maternal diet may increase pig performance (Exp. 2). In Exp. 1, 240 pigs were separated after weaning (28 d) into 2 groups depending on the presence of lactose in their diets. Pigs ( =120) fed diets with the precence of lactose (lactose +) were given prestarter (0-14 d) and starter (15-33 d) diets with 142 and 50 g/kg of sweet milk whey, respectively; the lactose-free group ( = 120) was offered an isoenergetic diet with 20 g/kg of porcine-digestible peptides (PDP; Palbio 62SP; Bioibérica S.A., Palafolls, Spain) and wheat replacing sweet milk whey. Choice and 1-feeder tests were performed in another group of animals ( = 72) to evaluate the preference and acceptance for both diets. Pigs preferred ( = 0.039) the lactose+ over the lactose-free diet after a 30-min choice test and consumed more ( = 0.001) lactose+ than lactose-free diet in a 1-feeder test. However, no difference ( > 0.467) in performance was observed between groups for the entire nursery period. In Exp. 2, 120 animals were obtained from sows that, during late gestation (14 d) and lactation (28 d), were fed diets containing 20 g/kg of PDP and another 120 animals were obtained from sows fed an isoenergetic diet without PDP inclusion. Placenta samples were collected at farrowing to assess the volatile compounds present in the placental fluid of sows. After weaning, all pigs received a feed containing 20 g/kg of PDP in the prestarter and starter diets. A principal components analysis of the total volatile compounds showed the exclusive presence of sulfur-containing compounds and a higher presence of terpene compounds in the placental fluid of PDP-supplemented sows. In addition, pigs coming from sows fed diets supplemented with PDP tended to show a higher ADFI ( = 0.07) and ADG ( = 0.06) than did pigs coming from control sows during the 15 to 33 d after-weaning period. These results suggest that dietary incorporation of sweet milk whey may be replaced by a specific protein source without affecting performance of pigs after weaning. However, more experiments are needed to elucidate the mechanism for the sow's diets' influence over pig's performance.

Influence of dietary electrolyte balance on feed preference and growth performance of postweaned piglets.

A total of 672 male and female piglets (21 d postweaning; approximately 13 kg BW) were selected to be used in 3 different experiments to assess the influence of dietary electrolyte balance (dEB; Na + K - Cl, in mEq/kg of diet) on feed preference and growth performance. In Exp. 1, piglets were fed 4 isoenergetic diets differing in dEB level: 16, 133, 152, and 269 mEq/kg diets. Changes on dEB were obtained by changing the levels of sodium and chloride with calcium chloride, calcium carbonate, and sodium bicarbonate. Piglets fed the 16 and 133 mEq/kg diets achieved a greater ADG (P < 0.04), BW (P < 0.04), and apparent total-tract digestibility of CP and Zn (P < 0.05) than did piglets fed the 269 mEq/kg diet. The 16 mEq/kg level also reduced blood total CO (P < 0.01), bicarbonate (P < 0.01), and base excess (P < 0.02) concentrations compared with the rest of the dietary treatments. Three diets differing in dEB were designed for Exp. 2 and 3: -16, 151, and 388 mEq/kg diets. In Exp. 2, greater ADFI (P = 0.03), BW (P = 0.02), ADG (P < 0.001), and G:F (P < 0.01) were observed for piglets fed the -16 mEq/kg diet than those fed the 388 mEq/kg diet. Subsequently, their short-term preference for these diets was assessed by using a 2-d choice-test protocol (30 min). Piglets preferred (P < 0.001) the 388 mEq/kg diet to the -16 mEq/kg diet, independently of the dietary treatment they received before. Pigs also preferred (P < 0.001) the 151 mEq/kg diet when compared with the -16 mEq/kg diet. Experiment 3 assessed the long-term preference and short-term consumption of the -16 and 388 mEq/kg diets. Similar to Exp. 2, animals showed a greater (P < 0.001) intake of the 388 mEq/kg diet than they did of the -16 mEq/kg diet during both the preference (14 d) and 1-feeder (2 h) tests conducted. Results show that low rather than high dEB levels optimize growth performance of piglets. When they have the opportunity to choose, piglets are unable to select the diet that optimizes their performance, either in short- or in long-term preference tests, showing also a greater short-term consumption of high instead of low dEB levels.

Dietary energy density affects the preference for protein or carbohydrate solutions and piglet performance after weaning.

Physiological state or dietary nutrient content can be determinants of the sensory perception with consequences for feed preferences. The aim of the present study was to assess whether the preference for protein or carbohydrate of piglets is affected by dietary energy density. In total, 240 weanling piglets (28 d old; initial BW 7.2 ± 1.1 kg) were allocated to 24 pens (10 pigs/pen) according to BW. Piglets were split up into 2 groups and had ad libitum access to a high energy (HE; 3.90 Mcal DE/kg; crude fat 129 g/kg) or a low energy (LE; 3.35 Mcal DE/kg; crude fat 60 g/kg) diet with similar CP content (190 g/kg). Piglet performance and preference for protein [porcine digestible peptides (PDP; Palbio 62SP, Bioibérica, Palafolls, Spain) 20 g/L] or carbohydrate (sucrose 20 g/L) solutions were measured on days 14 and 21 after weaning using a double-choice test (DCHT). The LE diet promoted a higher (P < 0.05) ADFI and ADG than the HE diet. Final BW on day 21 was higher (P < 0.001) for piglets fed the LE diet than piglets fed the HE diet (12.8 vs. 11.5 kg). Preference (P > 0.05) was not observed for protein or carbohydrate solutions on day 14 or 21 in piglets fed the LE diet. On the other hand, piglets fed the HE diet had higher (75% on day 14 and 65% on day 21; P < 0.01) preference for the sucrose solution. Dietary energy level and consequent nutrient imbalances, such as dietary protein-to-energy ratio, may affect feed preference for protein or carbohydrate solutions in piglets.