The impact of immune system stimulation (ISS) on the ileal nutrient digestibility and utilisation of dietary methionine plus cysteine (SAA) intake for whole-body protein deposition (PD) was evaluated in growing pigs. For this purpose, sixty barrows were used in two experiments: thirty-six pigs in Expt I and twenty-four pigs in Expt II. Pigs were feed restricted and assigned to five levels of dietary SAA allowance (three and two levels in Expt I and II, respectively) from SAA-limiting diets. Following adaptation, pigs at each dietary SAA level were injected with either increasing amounts of Escherichia coli lipopolysaccharide (ISSþ; eight and six pigs per dietary SAA level in Expt I and II, respectively) or saline (ISS2; four and six pigs in Expt I and II, respectively) while measuring the whole-body nitrogen (N) balance. After N-balance observations, pigs were euthanised, organs were removed and ileal digesta were collected for determining nutrient digestibility. Ileal digestibility of gross energy, crude protein and amino acids was not affected by ISS (P.0·20). ISS reduced PD at all levels of dietary SAA intake (P, 0·01). The linear relationship between daily dietary SAA intake and PD observed at the three lowest dietary SAA intake levels indicated that ISS increased extrapolated maintenance SAA requirements (P,0·05), but had no effect on the partial efficiency of the utilisation of dietary SAA intake for PD (P. 0·20). Physiological and metabolic changes associated with systemic ISS had no effect on the ileal digestibility of nutrients per se, but altered SAA requirements for PD in growing pigs.

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Impact of feeding n-3 fatty acids ( FA ) to ISA brown and Shaver white breeders and their progeny on bone development in pullets was investigated. Breeders were fed Control ( CON ); CON + 1% microalgae ( DMA : Aurantiochytrium limacinum ) as the source of docosahexaenoic acid; and CON + 2.6% of a co-extruded mixture of full-fat flaxseed ( FFF ) and pulses mixture as source of α-linolenic acid. Test diets (DMA and FFF) were balanced for total n-3 FA and n-6: n-3 FA ratio. Samples of day-old progeny were euthanized for bone mineral content ( BMC ) and tibia collagen type II. The remaining pullets were fed posthatch treatments as follows: from breeder CON: CON ( CON-CON ), DMA ( CON-DMA ), and FFF ( CON-FFF ), from breeder DMA: CON ( DMA-CON ) and DMA ( DMA-DMA ) and from breeder FFF: CON ( FFF-CON ) and FFF ( FFF-FFF ). A total of 60 pullets per posthatch diets were reared in cages (12 pullets/cage, n = 5) with free access to feed and water, bled at 6, 12, and 18 wk of age ( WOA ) for bone turnover markers and necropsied at 18 WOA for tibia and femur samples. Day-old pullets from breeder fed CON had greater BMC ( P < 0.001) relative to those from breeders fed other diets. There was strain and diet interaction ( P ≤ 0.024) on tibia breaking strength ( TBS ) and tibia cortical ash concentration at 18 WOA such that diet responses were only observed in Shaver white pullets. In this context, TBS of DMA-DMA and FFF-FFF was greater than for pullets originating from CON breeder, and the cortical ash weight of DMA-DMA and FFF-FFF pullets was 23.8 and 20.2%, respectively, higher than for CON-CON pullets. In conclusions, the strain effects were strong on tibia attributes on 18-week-old pullets. Breeder feeding of n-3 FA was more effective when concomitant with posthatch feeding of n-3 FA in supporting the skeletal strength and cortical bone development in Shaver white pullets. Further investigations are warranted to establish the impact these strategies on skeletal health during laying cycle.

There is limited information on feeding egg-type chick breeders n−3 polyunsaturated fatty acids ( PUFA ) and its impact on hatching egg quality and embryonic fatty acid ( FA ) utilization. We investigated the effects of feeding brown and white egg-type chick breeders diets containing sources of n−3 PUFA on egg composition, apparent embryonic FA utilization, and intestinal FA transporter in hatchlings. Twenty-six-week-old ISA brown and Shaver white breeders were fed either 1) control ( CON ); 2) CON + 1% of microalgae (DMA, Aurantiochytrium limacinum ) fermentation product, as a source of docosahexaenoic acid ( DHA ); or 3) CON + 2.60% of coextruded full-fat flaxseed and pulse mixture (FFF, 1:1 wt/wt) as a source of α-linolenic acid ( ALA ). Test diets had similar total n−3 and n−6:n−3 ratio. Eggs were hatched, and residual yolk ( RY ) samples taken for FA analyses. Apparent embryonic FA utilization was calculated by subtracting concentration of FA in RY from concentration of FA in yolk before incubation. There was an interaction between strains and diets ( P < 0.05) on DHA in phospholipid and triglyceride fractions of yolk. Both n−3 PUFA sources increased DHA to a greater extent in Shaver white than in ISA brown. The interactive effect of strains and diets ( P = 0.019) on embryonic utilization of ALA was such that DMA and FFF reduced ALA utilization, and this pattern was more prevalent in Shaver white birds than in ISA brown birds. There was no interaction between strains and diets on DHA utilization ( P > 0.05). Embryos from hens fed n−3 PUFA sources used less total FA in phospholipid fraction ( P < 0.001), and they preferentially used more DHA than CON embryos. Shaver white embryos used more ( P < 0.05) ALA and DHA than ISA brown embryos. Although data suggested Shaver white had higher propensity of depositing DHA than ISA brown, irrespective of strain, feeding n−3 PUFA modified embryonic pattern of FA utilization toward utilization of DHA.

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