PSVII-27 Effects of dietary near ideal amino acid profile on amino acid utilization efficiency for milk production in sows under thermoneutral or heat stress conditions

The objective was to estimate essential AA (EAA) utilization efficiency for milk production in sows (n = 24) fed control (19.6% CP) or reduced CP (RCP; 14.2% CP) diets under thermoneutral (TN; 21±1.5°C) or cycling heat stress (HS; 32±1.5°C daytime and 24±1.5°C nighttime) conditions. We hypothesized that RCP fed lactating sows with supplemental AA have increased EAA efficiency for milk production under TN and HS conditions. Diets contained 0.90% SID Lys and 2,580 kcal/kg. Sow BW and backfat were recorded on d 1 and 21 to estimate body protein mobilization (BPM). Piglet BW was recorded on d 1 and 21 to estimate milk yield. Amino acid efficiencies were calculated based on milk AA output relative to SID AA intake corrected for AA contribution from BPM. During HS, N, Arg, His, Ile, Leu, Lys, Met, Phe, Thr, Trp, and Val efficiency for milk production did not differ between sows fed control (42, 26, 44, 36, 39, 49, 52, 32, 50, 43 and 44%, respectively) and RCP (56, 39, 51, 49, 56, 47, 42, 39, 50, 59 and 41%, respectively) diets. Compared to control sows, RCP sows had greater (P < 0.05) efficiency of Arg (30% vs. 61%) under TN condition. Efficiencies of His, Ile, Leu, Phe, and Trp tended to be greater (P = 0.07, 0.06, 0.06, 0.07 and 0.06, respectively) in RCP compared to control sows (50, 41, 44, 36, and 50% vs. 74, 67, 75, 54 and 78%, respectively). Efficiencies of Lys, Met, Thr, Trp and Val did not differ between control and RCP sows (56, 59, 57, and 50% vs. 67, 59, 69 and 57%, respectively). In summary, an RCP diet improved efficiency of N, Arg, His, Ile, Leu, Phe, and Trp for milk production in lactating sows under TN but not HS conditions.

Feeding sows during the transition period—is a gestation diet, a simple transition diet, or a lactation diet the best choice?1

Three experiments were carried out to study whether a gestation diet, a simple transition diet, or a lactation diet is the best choice in late gestation and when sows preferably should be transferred to a high crude protein (CP) lactation diet. In experiment 1, 35 sows were fed either a gestation diet (12.1% CP), a lactation diet (15.9% CP), or a 50/50 mix (simple transition diet; 14.0% CP) from 6 d before parturition until parturition, to study the impact on farrowing and colostrum performance. In experiment 2, 90 sows were studied from 6 d before parturition until weaning at day 24 and they were fed one of five strategies: a gestation diet until day 3 or day 10 of lactation (strategy 1 and 2) and then lactation diet; a simple transition diet until day 3 or day 10 (strategy 3 and 4) and then lactation diet; or a lactation diet throughout the study (strategy 5). In experiment 3, 124 sows were fed strategy 1 or 5. Sows were weighed and back fat (BF) scanned when entering the farrowing unit and at day 2, 10, 17, and 24. Piglets were weighed at birth and after 24 h, and colostrum production was studied (experiment 1). Litter weight at day 2, 10, 17, and 24 was recorded, milk and blood samples were collected weekly and sow fat and protein mobilization, and balances of energy, N, and Lys were calculated from day 3 to 10 of lactation (experiment 2). Total- and live born piglets, and frequencies of stillbirth and piglet diarrhea were recorded (experiment 3). Feeding sows a gestation diet, a simple transition diet, or a lactation diet showed no evidence of effects on colostrum production or farrowing process (experiments 1 and 3) or lactation performance (experiments 2 and 3). Compared to previous studies, sows had a poor milk yield. Plasma urea was elevated (P < 0.001) indicating CP oversupply prior to parturition in sows fed the lactation diet as compared with the two other diets. According to calculated balances, all dietary strategies supplied insufficient amounts of N and Lys from day 3 to 10, indicating that the best choice is to feed sows with a high CP lactation diet from parturition and onwards. Primiparous sows had a higher plasma insulin concentration (P < 0.01), lower colostrum yield (P < 0.01), and higher frequency of piglet diarrhea (P < 0.001) than multiparous sows. In conclusion, in our conditions (high CP in gestation diet; poor milk yield; restricted feeding in early lactation), sow performance was not compromised by the dietary strategies, but results indicate that primiparous and multiparous sows should be fed differently.

Influence of kinetin on storage protein mobilization and ultrastructure of plastids in excised lupine cotyledons grown in darkness

Storage protein disappeared first from the peripheral and later from central parts of the lupine cotyledon. Kinetin (500 μM) stimulated this process; its effect was most prominent after longer times of incubation. In plastids large, crystalline prolamellar bodies were observed. They some-times split into smaller parts during the course of the experiment, especially in the kinetin-treated material. Kinetin in darkness did not stimulate formation of thylakoid membranes (neither grana nor primary lamellae).