BACKGROUND: The aim of the study was to rank conventionally used fibre rich feeds for their physicochemical properties and detect possible correlation between analytical fibre determinations. A total of 22 samples were analysed for proximate fibre values, soluble dietary fibre (SDF), insoluble dietary fibre (IDF), crude protein (CP) and crude ash (CA). Physicochemical properties were determined in vitro by hydration capacity (HC) [water holding capacity (WHC), water binding capacity (WBC), swelling property (SwP)] and buffering capacity [linear buffering rate (LBR)].RESULTS: Fibre content and physicochemical properties varied markedly between the samples. HC was highest for beet pulp and lowest for rice and millet bran. Buffering capacity expressed minimum values for lignocelluloses and maximum values for rape seed hulls. The correlation of methods was positively between WBC, WHC and SwP (r ≤ 0.89; P ≤ 0.003) but not significant for HC and buffering capacity. SwP negatively correlated with crude fibre (CF), neutral detergent fibre (aNDF_OM) and IDF (r ≤ −0.48; P ≤ 0.05). WBC and SwP positively correlated with SDF (r ≤ 0.63; P ≤ 0.04). LBR was negatively correlated with CF, aNDF_OM, IDF and total dietary fibre (r ≤ −0.55; P ≤ 0.02), but positively with CP (r = 0.53; P = 0.01).CONCLUSION: The determination of physicochemical properties is applicable to rank fibre rich feeds, some correlations between fibre analytical measurements and physicochemical properties were detected. © 2019 The Authors. Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry

A feeding trial with 96 piglets was performed to investigate the effect of added soluble (SDF) and insoluble dietary fibre (IDF) sources on performance, apparent total tract digestibility (ATTD), concentration of microbial metabolites and pro-inflammatory marker genes as indicators for immune response. Piglets were allotted to four treatments (T): T1 control, T2 with soybean hulls (IDF/SDF: 8.35) and T3 and T4 with two different kinds of lignocellulose (IDF/SDF: >70). Diets were isofibrous for their value of total dietary fibre to underline the particular physicochemical properties of fibre sources. No differences were observed regarding average daily feed intake, average daily gain (ADG), feed conversion ratio and body weight, while T2 expressed higher ADG in the grower phase (day 14-54) vs. T3. Soybean hulls (T2) resulted in higher ATTD of dry matter and organic matter vs. T4; ether extract vs. T1 and neutral detergent fibre vs. T1, T2 and T3. The concentration of short chain fatty acids did not differ among treatments. Ileal digesta in T2 generated higher amounts of cadaverine vs. T3 and T4, likewise T1 vs. T4. Finally, no impact on immune response was detected. In conclusion, soybean hulls affected ATTD positively and lignocellulose prevented the formation of cadaverine, no overall direct response of SDF nor of IDF for the inclusion level were observed.

This study investigated the effects of sorghum ensiled as whole grains with different dry matter concentrations on the apparent total tract digestibility (ATTD) of energy, crude nutrients and minerals in growing pigs. Whole grain sorghum batches with varying dry matter (DM) concentrations of 701 (S1), 738 (S2) and 809 g kg⁻¹ (S3) due to different dates of harvest from the same arable plot, were stored in air-tight kegs (6 L) for 6 months to ensure complete fermentation. Subsequently, 9 crossbred barrows (34.6 ± 1.8 kg; (Duroc x Landrace) × Piétrain)) were used in a 3 × 3 Latin square feeding experiment. Diets were based on the respective sorghum grain silage and were supplemented with additional amino acids, minerals and vitamins to meet or exceed published feeding recommendations for growing pigs. The ATTD of gross energy, dry matter, organic matter, nitrogen-free extracts, and crude ash were higher in S1 compared to S3 treatments (p ≤ 0.05), while S2 was intermediate. Pigs fed S1 showed significantly higher ATTD of phosphorus (P) compared to all other groups while ATTD of calcium was unaffected irrespective of the feeding regime. In conclusion, growing pigs used whole grain sorghum fermented with a DM concentration of 701 g kg⁻¹ (S1) most efficiently. In particular, the addition of inorganic P could have been reduced by 0.39 g kg⁻¹ DM when using this silage compared to the variant with the highest DM value (809 g kg⁻¹).

This study examined the effects of short-term dietary zinc (Zn) and phosphorus (P) variations on the mobilizable bone Zn pool and overall Zn status in adult laying hens. Forty-eight hens (50% Lohmann Brown Classic, 50% Lohmann LSL Classic) were housed in pairs (one hen per breed per pen) across 24 pens. The pens were randomly assigned to one of two dietary P levels (0.37% or 0.84% in DM) using a high-protein corn-soybean diet (11.4 MJ AME/kg, 21.5% CP) during a 14-day acclimatization period. Following acclimatization, pens from both P groups were further randomized into four dietary treatments in a 2 × 2 factorial design, varying in P levels (low vs. high) and Zn supplementation (28 vs. 131 mg/kg) over an 8-day experimental feeding phase. Performance metrics, egg production and quality, and tissue mineral concentrations (plasma, liver, bone, and eggs) were measured. Statistical analyses were performed using linear mixed models in SAS 9.4, incorporating random effects of pen nested within treatment group and fixed effects of dietary P, dietary Zn, breed, and their interactions. Tukey-corrected 95% confidence intervals were used to estimate effect differences, with significance set at P < 0.05. Performance metrics, including egg production and body weight, were unaffected by dietary treatments (P > 0.1), indicating no clinical symptoms of Zn deficiency. However, hens on low-Zn diets exhibited significant reductions in plasma Zn concentration (-0.83 mg/L; P = 0.0008) and liver Zn concentration (-6.78 mg/kg DM; P = 0.01), confirming subclinical Zn deficiency. Low-Zn diets also increased the femoral molar Ca:P ratio by 0.15 (P = 0.01), irrespective of dietary P supply. Interestingly, low-P diets led to a significant reduction in femur Zn content (-0.46 mg; P = 0.0009), regardless of Zn supplementation, following 21 days of reduced P feeding. These findings highlight the higher susceptibility of laying hens to phytate antagonism compared to broilers, as evidenced by measurable subclinical Zn deficiency under short-term Zn deprivation. Additionally, a temporary suspension of mineral P supply appeared to impair the mobilizable bone Zn pool. The underlying functional mechanisms driving these interactions remain unclear and warrant further investigation.