The objective of this study was to evaluate the effect of a combined low-protein (CP) lowphosphorus (P) diet, supplemented with limiting amino acids and microbial phytase, on performance, nutrient utilization and carcass assessment of grower-finisher barrows. 4 · 6 crossbreed barrows were continuously housed in metabolism cages from 25 to 100 kg live weight and were fed diets, either conventional according to recent nutrient recommendations (A) or protein reduced (B) or protein and phosphorus reduced diets (C) based on barley (59-80%), maize (15%) and soybean meal (23-2%). Diet A (positive control) contained in fresh matter 18.5%, 15.6% and 13.6% CP and 0.59%, 0.51%, 0.50% P (growth phases I: 25-50 kg, II: 50-75 kg, III: 75-100 kg weight). Diet B was low in CP (14.2%, 13.4%, 11.0%), diet C low in CP and low in P (CP: as B, P: 0.46%, 0.41%, 0.32%). Diet D served as a negative control (CP and P as C). To diet B the limiting amino acids lysine, methionine, threonine and trypthophan were added to meet the levels in diet A, to diet C the limiting amino acids and 800 FTU Aspergillus-phytase per kg were supplemented. At the end of the balance periods of about 100 (A,B,C) or 133 (D) days, the barrows were slaughtered at 100 kg live weight, the carcasses scored and loin, biceps femoris, os femoris and phalanx prima IV were analysed for their nutrient (dry matter, protein, fat) or mineral (ash, Ca, P, Mg, Fe, Zn) composition. In contrast to the basal diet D, the CP or P reduction in diets B and C did not negatively affect growth, feed efficiency, nitrogen retention or overall carcass performances of the pigs. With the low CP diets B and C, N excretion via the urine was significantly reduced and thus N excretion per unit weight gain was decreased by about 30%. The addition of microbial phytase (C) increased apparent digestibility of P significantly between 25% (growth phase III) and 50% (growth phase II). In spite of 25% reduction of P intake (C), the absolute daily P retention did not differ between treatments. Thus phytase supplementation in diet C reduced P excretion per unit weight gain by about 35% (I, II) to 44% (III) as compared with A and B. Similarly, phytase raised apparent digestibility of Ca by about 25% and Zn by about 80%. Generally, the carcass and meat characteristics were not affected by any of the diet strategies employed in this experiment. Mineralization (bone weight, ash, Ca, P, Mg) of the os femoris and phalanx prima IV were also similar in all treatment groups. However, phytase supplementation led to significantly increased zinc concentration in bones, indicating considerably improved zinc release from the phytate complex. In contrast, Fe incorporation into the os femoris was significantly reduced in the phytase group. In general, the low CP and low P feeding regimen introduced in this experiment offers substantial benefits in maintaining a sustainable environmentally-friendly pork production.

The objective of this study was to evaluate the effect of a combined low-protein, low-phosphorus diet supplemented with limiting amino acids and microbial phytase on performance, nutrient utilization and carcass characteristics of late-finishing barrows. 4 x 8 crossbreed barrows were continuously housed in metabolism cages from 70-110 kg BW and were fed diets, either conventional (A) or protein reduced (B) or protein and phosphorus reduced diets (C) based on barley, maize and soybean meal. Diet A (positive control) contained in air dry matter 13% and 10% CP as well as 0.49% and 0.42% P at growth phases I (70-100 kg BW) or 11 (100-110 kg BW), respectively. Diet B was low in CP (11.3%, 8.4%), diet C low in CP and low in P (CP: as B, P: 0.36%, 0.30%). To diet B the limiting amino acids lysine, methionine, threonine and trypthophan were added to meet the levels in diet A. To diet C the limiting amino acids and 800 FTU/kg Aspergillus-phytase were supplemented. At the end of the balance periods the barrows were slaughtered, the carcasses scored and loin chops, ham and Phalanx prima IV were analysed for nutrients and minerals. The CP or P reduction in diets B and C did not generally negatively affect growth, feed efficiency, absolute nitrogen retention or overall carcass performances of the pigs. With the low CP diets B and C, N excretion per unit BWG was decreased by about 23%. The addition of microbial phytase (diet C) increased apparent total tract digestibility of P by about 20%. In spite of 30% reduction of P intake (diet C), the absolute P retention related to 1 kg BW did not differ between treatments. Thus, phytase supplementation in diet C reduced P excretion per unit BWG by about 33%. Phytase raised apparent digestibility of Zn by about 20% but not Ca digestibility. Generally the carcass traits and meat characteristics were not affected by any of the diet strategies. Mineralization of the Phalanx prima IV was also similar in all treatment groups. However, phytase supplementation led to significantly increased zinc concentration in bones (25%). In contrast, Fe incorporation into the Phalanx prima IV was not affected. In general, the feeding regimen introduced in this experiment offers substantial benefits in maintaining a sustainable environmental-friendly pork production even at the stage of late-finishing barrows.

2 x 6 pigs continuously housed in metabolic cages from 25-100 kg weight were fed N-reduced diets based on barley, maize and soybean meal. Diet I (control) contained in FM (fresh matter) 0.56%, 0.48% and 0.46% P (feeding phases A: 25-50 kg, B: 50-75 kg, C: 75-100 kg weight) and 0.76%, 0.71% and 0.68% Ca. Diet II was low in P (0.46%, 0.40%, 0.32%) and Ca (0.69%, 0.62%, 0.52%) and 800 U Aspergillus-phytase per kg were added. Analyzed cadmium concentrations in diet I were 23.4, 19.9 and 13.7 micrograms/kg FM and 20.6, 14.9 and 12.7 micrograms/kg FM in diet II respectively. At 100 kg weight in both treatment groups low cadmium concentrations in liver (11.8 vs. 17.3 micrograms Cd/kg FM) and kidneys (59.6 vs. 102 micrograms Cd/kg FM) were found. Contrary to findings for rats fed semisynthetic diets enriched with high CdCl2 levels, phytase supplementation to the P- and Ca-reduced pig diet with a low Cd concentration significantly enhanced liver and kidney cadmium accumulation. Differences in dietary Cd levels, the binding form of Cd in the diets and the duration of the experimental trials may partially explain the differences found between rats and pigs. Complex interactions between cadmium and various elements, especially calcium, might also have additionally influenced the carry over of cadmium in the present study. Irrespective of the dietary treatment, liver and kidney cadmium concentrations in both groups were considerably lower than maximal permitted values.

Zusammenfassung Zwei verschiedene Herkünfte der Einzelleralge Scenedesmus acutus, Stamm 276–3a, wurden in Versuchen mit Schweinen und Masthähnchen auf folgende Qualitätskriterien untersucht: Chemische und biologische Eiweißqualität, Verträglichkeitsgrenze, spezifische Wachstumsfaktoren, Carotintransformation und Carotinoid‐Einlagerung in Geflügelgewebe. Scenedesmus acutus weisen eine ernährungsphysiologisch günstige Aminosäuren‐zusammensetzung mit einem EAS‐Index von etwa 76% auf. Methionin und Isoleucin sind nach dem EPV die limitierenden Aminosäuren. Die hohe Biologische Wertigkeit des Algenstammes Scenedesmus acutus 276–3a wird in 2 Versuchsreihen mit Schweinen bestätigt. Bei Geflügel stellt sich mit ca. 10% Algensubstanz in der Ration eine Toleranzgrenze ein. Der wirtschaftlich vertretbare Einsatzbereich dürfte zwischen 3–5 % liegen. Die in den Algen enthaltenen natürlichen Farbstoffe führen zu einer ausgeprägten Carotinoid‐Einlagerung im Tierkörper und sind damit begrenzend. Spezifische stimulierende Wachstumsfaktoren ließen sich in den Algen experimentell nicht nachweisen. Eine vermutete geruchsstabilisierende Wirkung auf die Faeces konnte nicht beobachtet werden. Bei ausgeglichener Vitamin‐A‐Versorgung aus der Grundration läßt sich keine zusätzliche Vitamin‐A‐Wirksamkeit des Algen‐β‐Carotins experimentell nachweisen.

Zusammenfassung Bei 3 Ferkeln einer Vergleichsgruppe um 5 kg KM und 4 × 2 Ferkeln nach 45 Tagen im Bilanzversuch und 23 kg KM wurden die Ganzkörper in 7 Teilfraktionen (Schlachthälfte, GI‐Trakt, Leber, Herz und Nieren, Blutserum, Blutkorpuskeln, Restinnereien) zerlegt und deren Homogenate auf den Gehalt an essentiellen und nicht essentiellen Aminosäuren (AS) untersucht. Das gemessene AS‐Muster wurde auf eine mögliche Beeinflussung durch Zulagen von 1,5% Fumarsäure bzw. 1,5% Citronensäure in den Futtermischungen überprüft. Die untersuchten Körperfraktionen zeigten jeweils ein spezifisches AS‐Muster. Alterseinflüsse auf die AS‐Zusammensetzung waren nachweisbar, aber unterschiedlich auf einzelne AS bzw. Fraktionen verteilt. Die Zulagen von Fumarsüure und Citronensäure hatten keinen statistisch absicherbaren Einfluß auf das AS‐Muster im Körper.